Art. LXVI.—Notes on New Zealand Cetacea.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 9, 1876, Page 477

Art. LXVI.—Notes on New Zealand Cetacea. By James Hector, M.D., C.M.Z.S. [Read before the Wellington Philosophical Society, 1876.] Tursio metis. Gray, “Cat. Seals and Whales,” 256; Hector, “Trans. N.Z. Inst.,” V., 162; Hutton, Id., VIII., 180. Plates. This species was founded on a skull in the British Museum, but its habitat was unknown until I determined its occurrence on the New Zealand coast from an imperfect skull obtained in Dusky Bay in 1872. Two specimens were captured by Capt. Fairchild in the same locality in 1875, the smaller of which has been described shortly by Capt. Hutton; and the skeleton of the other, which has been placed in the Colonial Museum, I have now to describe. The total length of the animal in the flesh was noted as 9 ½ feet. This agrees with the length of the skeleton on making the usual allowance for the intervertebral cartilage and soft parts, as follows:— Inches. Length of skull 19 Total length of vertebral centra 76 Soft parts of snout 2 Caudal 9 Intervertebral cartilage 8 104 = 9ft. 6in. Skull.—Cranial portion moderate, rounded behind, with large prominent condyles and parietal crests; nasal bones prominent but rounded; posterior maxillary area steep; supra-orbital horizontal, with rough margin round

the notch, and a flat area extending forward to the middle of the beak; premaxillaries only slightly shorter posteriorly, with a comparatively small depressed triangular area in front of the nasal aperture, which is crescentic; rostrum bevelled, with a narrow intermaxillary groove widening towards the tip. Palate flat, contracted behind, with a mesial groove towards the tip, in which the premaxillæ and the vomer are exposed. Dental groove divided into large deep alveoli, and extending along the margin of the beak, as far back as a constriction, which occurs two inches in advance of the notch. Lowerjaw massive, 23/23 = 23/23, irregular. Teeth 1.3 inches in length, the exposed portion being bluntly conical and incurved, and the fangs generally crooked. Ear-bell triangular, moderately solid, with a deep groove on the exterior. It measures 1.5 × 8 inches. Vertebrœ.—Cervical, seven in number, have the atlas and axis anchylosed, forming a solid mass, with the spinous process compressed, beak-like, and directed backwards. Width of the anterior articular surface is 4.3 inches. The posterior cervicals are very short and compressed, and have large slender neural arches, the third cervical only has a lateral foramen, and the seventh is without any inferior lateral process. The dorsals are twelve in number, and have stout lateral processes, which from the eighth to the eighteenth vertebræ spring from the neural arches, and then descend on to the centrum. The posterior vertebræ have thin expanded processes and rounded centra as far as the 38th, where the metapophysis and chevron bones commence. The first appearance of a lateral foramen, is on the 46th. The lateral process disappears on the 48th, and the 54th is the last vertebra that has a neural canal. The chevron bones, seventeen in number, extend from the 38th to the 55th vertebra. The centra of the caudals are oblong, and taper rapidly in size from the 55th to the 64th. Ribs.—The first rib is compressed, wide, and strongly curved. The first four only have tubercles. Sternum is narrow and elongated, and consists of four segments, which are strongly united, the anterior being expanded into one anterior and two posterior notches. There are five articular attachments on each side. Scapula triangular, the posterior margin ascending at 20° to the plane of the glenoid articulation. Anterior superior angle is produced and slightly hooked over the acromion process, which is much expanded and incurved, while the corocoid is also thin and expanded, and at the tip is curved outwards on the prescapular fossa.

Paddle bones.—The humerus is short and stout, with a large tuberosity. The radius and ulna are one-third longer than the humerus, while the manus, though some of the terminal phalanges are lost, appears to have been about twice as long as the arm bones. Table of Measurements. Inches. Skull— Total length 19.0 Occipital height 8.0 Greatest width 10.5 Orbital width 8.0 Width at notch 5.5 " Middle of beak 4.0 " Premaxillaries 2.0 Length of triangle 4.5 Diameter of blowhole 2.5 Length of dental groove 9.0 " Lower jaw 16.5 Posterior height of do. 4.0 Anterior " " 1.7 Length of symphysis 3.0 Extreme Dimensions, including Neural Spine. Transverse. Vertical. Vertebrœ— Nos. 1st and 2nd 6.6 4.0 8th 5.0 4.0 14th 5.8 5.0 19th 9.8 5.8 27th 10.5 8.0 38th 7.0 6.0 48th 5.0 2.5 Size of Neural Canal and Centra. Canal. Centra. 8th 2 × 1.2 1.4 × 1.8 14th 1.7 × 1.5 1.6 × 1.5 19th 1.2 × 1.0 1.8 × 1.6 25th 1.1 × 0.8 1.1 × 0.8 38th 0.7 × 0.3

Length of Centra. Total Length. Inches. Atlas and axis 1.3 Nos. 3–7 1.3 8–11 4.0 12 3.0 18 11.2 19 1.5 20–25 9.0 26–30 7.0 30–37 9.1 38 1.3 39–41 4.2 42–51 15.5 52–54 4.5 55–64 6.0 Inches. Ribs— 1st.—Length of articular process 2.0 Width at the angle 1.3 Distance from head to tip 7.0 5th.—Articular process 3.0 Distance from head to tip 15.0 12th.—Styliform—Length 13.0 Sternum—Length 12.0 " Width of first segment 5.0 " " of middle 1.5 Scapula—Length 10.5 " Height 7.0 " Glenoid diameter 1.5 Humerus—Length 3.0 " Width 2.0 Ulna—Length 4.0 Manus 14.0 From the similarity of the external measurements to those of Delphinus forsteri, given by me (“Trans. N.Z. Inst.,” Vol. VI., p. 85), Captain Hutton has concluded that I have mistaken Tursio metis for that species overlooking my remark that the skull agreed with that described and figured by me in Vol. V., p. 162, Pl. III., and which has a prominent ridge on the palate and double the number of teeth. As the palatal aspect of the skull affords a ready means of distinguishing the skulls of our dolphins, which are

the parts of the skeletons more frequently brought under observation, and I cannot find that this aspect of the skulls heen anywhere published, I have arranged figures of the different specie convenience of comparison in Plate No. XI. Description of Plate xii. Fig 1. Cervical articulation. Fig 2. 8th Vertebra. Fig 3. 19th " Fig 4. 38th " Fig 5. 48th Vertebra. Fig 6. 1st Rib. Fig 7. Scapula. Fig 8. Sternum. Globicephalus macrorhynchus. Gray, “Zool. ‘Ereb.’ and Terror,'” p. 33; “Cat. Seals and Whales,” p. 320. Hector, “Trans. N.Z. Inst.,” Vol. II., p. 28; Vol. V., p. 164; Vol. VII., p. 261., Pl. XVI., figs. 1 and 2, (not Pl. XVI. * This figure was crowded out of the preceding Plate, and the wrong name affixed by a mistake of the draughtsman.., which is Orca pacifica). Globicephalus scammoni, Cope., “Proc. Phil. Acad.,” 1869, p. 22. Large-headed Pilot Whale, or South Sea Blackfish. Only a few skulls of this species were to be found in the European collections until Mr. Charles Traill obtained the two individuals at Stewart Island in January, 1874, the external characers of which I recorded in a former communication. The skeletons of these specimens are now in the British Museum, but in January last a school of Blackfish ran ashore in Lyall Bay, outside Wellington Harbour, and ten complete skeletons were secured. One of them, of a large male, in course of preparation for the Colonial Museum, I have now to describe. Mr. J. Buchanan, F.L.S., took the accurate drawing shown in Pl. XIII., as it lay stranded on the beach. The total length was nineteen feet from the snout to the fork of the tail. In form it was cylindrical in the forward part of the body, and compressed vertically in the posterior portion. The forehead blunt and globular, and separated from the snout by a groove. The blowhole situated over and slightly in advance of the eye. The dorsal fin rises over the middle and thickest part of the body. The anterior limb is elongate and acute. The colour was black, but with an ill-defined dark grey streak on each side of the back, and a double V-shaped streak along the belly, uniting at the vent, and a lighter patch over and behind the eye, but not being in any case sufficiently defined to admit of being described as bands. It is very doubtful if this species should be separated from G. melas, or the common Caaing Whale, of the North Atlantic, an excellent figure of which is given by Dr. Murie, F.Z.S.,† “Trans. Zool. Soc.,” Vol. VIII., Pl. XXX. and certainly no reason has been

shown for distinguishing under a new specific name the Blackfish of the Pacific, when it appears on the Californian coast. The Black fish has the same habits and range as the Sperm Whale, frequenting the subtropical seas in large schools, and occasionally, like the great Cachelot, extending their migrations to temperate latitudes, and even doubling Cape Horn. As there is now generally admitted to be only one species of Sperm Whale common to all seas, the division of the Pilot Whales into distinct species should require very definite proof, so that the skeletons which have been transmitted to various museums in Europe and America will enable an accurate comparison to be made with the northern forms, and settle this interesting question of distribution. The only differential characteristics are to be found in obscure shades and patches of lighter colour, and in the number and form of the teeth, which are notoriously mere individual characteristics among this group of Cetacea, the teeth showing a marked tendency to disappear wholly, or in part, in old individuals. Among the school of Pilot Whales under review some have only nine and others twelve teeth in the upper jaw, while the usual number in the lower jaw was ten. The great individual variety in the number and position of the teeth that are either absorbed or are lost early in life, becomes, however, still more marked among the Ziphioid Whales, and has led to the temporary establishment of species and even generic distinctions in numerous instances. The state of the bones proved that the animal was of mature age. The skull is 28 inches along the floor, with an extreme width behind the orbit of 19 inches. Of this total length the beak occupies exactly one-half (28 inches). It is broad, flat, and slightly bent down on the top. Its upper part is formed by an expansion of the callous premaxillaries, which are slightly depressed in the middle line between the notches, and are separated throughout by a wide groove. The entire vertex of the cranium is formed by the nasal bones, which are very prominent. The lower aspect of the beak is formed entirely of the maxillaries, the palatine bones only showing as a narrow band between the maxillæ and the pterygoids, and the premaxillaries only showing in this aspect as a small area on the top of the rostrum. The tooth series occupies the borders of the maxillæ for half their length, and show ten alveoli with raised margins, but some are almost obliterated. The lower jaw, which is rather slender, has nine alveoli in a groove, which is wider at the symphysis and narrow behind. The symphysis only extends back as far as the fourth tooth from the top.

Electra Clancula Clymenia Obscura Delphinus Forsteri Clymenia Novae Zealandiae Tersio Metis

Tursio Metis, Gray.

Clobiocephalus Macrorhyncus, Gray.

The number of vertebræ is as follows:— Cervical 7 Thoracic 11 Lumbar 13 Caudal with chevrons 29 — Total number 60 The first six cervical vertebræ are soldered into a solid mass by the adhesion of their centra and neural arches, the divisions being only distinctly visible on the lateral branches of the arches. The cervical mass formed by the spinous processes of the atlas, axis, and third vertebra, is directed backwards and is separated by a fissure from the posterior spine of the mass, which is composed on the left side of the sixth arch only, and on the right side by the fifth and sixth, the fourth segment having an incomplete arch. The length of the anchylosed vertebræ is 3–9 inches. The seventh vertebra is a compressed lammellate bone in all its parts. The centrum is 0.7 inch in length, and has a rough patch but no distinct articular facet for the attachment of the first rib. The arch is directed backward, and the transverse processes slightly downwards. There is no trace of an inferior transverse process. The dorsals, 11 in number (Nos. 8 to 18) have a total length of 38 inches. They gradually increase in length backwards, the body of the 8th being 1–6 and that of the 18th 3–6 inches. The transverse process of the ten anterior segments are stout and short, with a wide articular facet for the ribs. They rise on the side of the arch for the first five vertebræ, and then descend till, on the 18th, the process, which is longer and expanded like that of the surrounding vetebræ, springs from the upper third of the centrum. There is no costal articulation on the transverse process of this vertebra. The lumbar vertebræ are thirteen in number, the first chevron bone appearing between the 31st and 32nd vertebræ. No. 27, or the ninth lumber, is the largest in the spinal column, the length being 4–6 and the diameter of the centrum 4 inches, while the total length, including the neural spine, is 12 inches, and the width through the transverse processes is 13 inches. The hæmal surface is compressed and excavated on each side of a mesial ridge. The average breadth of the processes is 2–5 inches. The caudal vertebræ, 29 in number, continue to have centra of equal size as far as the ninth (No. 42), when they become compressed, though retaining the same height to No. 48, after which they rapidly decrease in size. The first vertical arterial foramen appears on No. 38, and on No. 42 the lateral process is reduced to a mere tubercle. The last trace of a spinal canal is on No. 48.

The first rib is a very stout, strongly curved, compressed bone, thirteen inches in length from tip to tip, while the fifth, which is longest, is twenty-six inches. Only the first seven have a double articulation with the vertebral column. The sternum consists of three segments, and shows four articulations, its total length being sixteen inches. The hyoid is a crescentic bone twelve inches in length. The pelvic bones are prismatic styliform bones, nine inches in length. The scapular is triangular and strongly ridged, the posterior edge forming an angle of 35° to the plane of the articulation. Acromion thin, expanded, and incurved; corocoid thicker; both three inches long, or one-fifth the length of the superior edge. Humerus and arm bones firmly united. Manus long and pointed, the second digit being the longest. The number of phalanges is as follows:— I., 4; II., 13; III., 10; IV., 3; V., 1. Description of Plates. Sketch of the External Form, pl. XIII. Cervical mass. Pl. XIIIa., Fig. 1. 13th vertebra. Fig. 2. 23rd " Fig. 3. 39th " Fig. 4. Scapula Fig. 5. 1st rib. Fig. 6. 5th Rib. Fig. 7. Sternum. Fig. 8. Hyoid bone. Fig. 9. Pelvic bone. Fig. 10, a, male; b, female.