Art. LI.—On the Leg-bones of Meionornis from Glenmark.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 29, 1896, Page 557

Art. LI.—On the Leg-bones of Meionornis from Glenmark. By Captain F. W. Hutton, F.R.S., Curator of the Canter-bury Museum. [Read before the Philosophical Institute of Canterbury, 6th May, 1896.] No deposit of moa-bones has as yet been found when draining the swamps on the Canterbury Plains. They only occur among the low hills surrounding the plains, and of these by far the most important was that at Glenmark. The earlier finds here were in 1866 and 1867, and some account of the bones is given by Sir Julius von Haast in the first volume of the “Transactions of the New Zealand Institute.” But a still larger find was made in 1872, of which there is no record.

The bones were found chiefly in an old swamp, covered by from 4ft. to 12ft., or even more, of peat. They were accompanied by bones of Harpagornis, Aptornis, and Cnemiornis, Apteryx australis and A. oweni, Ocydromus (sp.), and Sphenodon punctatus. Dr. Von-Haast also mentions bones of Nestor and of Anas finschii, but they are not now in the Museum. In his description of the locality he points out that the alluvial river-beds are older than the swamp deposit, but that there is no difference in the species of moas found in each. He says, “All the different species, as it were, have appeared together, and have afterwards become extinct about the same time.”*“Geology of Canterbury and Westland,” Christchurch, 1879, p. 443. The Glenmark collections have been dispersed over nearly the whole world, and it is impossible now to arrive at any accurate results as to the relative numbers and measurements of the different species found there; but there are still in the Museum 126 metatarsi, 131 tibiæ, and 116 femora of Meionornis, collected in the swamp, and these are sufficient to give a correct idea of the sizes of the species of this genus. With this object in view, I have measured all these bones, and tabulated them in the same way as I did those from Kapua and Enfield, and arrive at the following results :— Meionornis casuarinus. This species is smaller and more slender than at Kapua or Enfield, the average length of the metatarsus being 210mm. (8.25in.); of the tibia, 463mm. (18.25in.); and of the femur, 263mm. (10.5in.). It is the “No. 3, D. casuarinus, smallest size,” of Dr. Von Haast's paper in the first volume of the “Transactions of the New Zealand Institute.” The accompanying diagram gives the two principal measurements of all the leg-bones, and shows that there is only a single point of concentration in each. Consequently there is no evidence of three distinct sizes, as supposed by Dr. Von Haast. M. casuarinus appears to have been at Glenmark nearly four times as common as M. didinus. The following are the numbers of the bones: Metatarsi, about 97; tibiæ, 104; femora, about 90. Meionornis didinus. This species is about the same size as at Kapua and Enfield, but it is not so well marked off from M. casuarinus; indeed, no line can be drawn dividing either the metatarsi or the femora of the two species. It is only the tibiæ which are distinctly separated, and even with this bone the point of concentration is on the side nearest to M. casuarinus. It is No. 4, D. didiformis, largest size,” of Dr. Von Haast's paper already referred to. The following are the numbers of the bones: Metatarsi, about 31; tibiæ, 27; femora, about 26.

Length of the metatarsus, 184mm. (7.25in.); of the tibia, 393inm. (15.5in.); and of the femur, 254mm. (10in.). General Remarks. The differences thus shown to exist between the birds from Glenmark and those from Kapua and Enfield are probably due to differences in the age of the deposits. Geological considerations would favour the idea that the Enfield deposit was the youngest of the three, as the bones, were, close to the surface, while the fact that M. casuarinus and M. didinus are less differentiated from each other at Glenmark than at the other places may be taken as palæontological evidence that it is the oldest; and, arranging the deposits in this order, we have the average dimensions of the leg-bones of the two species as follow:— Meionornis Casuarinus. Metatarsus. Tibia. Femur. — Length. Prox. Width. Mid. Width. Distal Width. Length. Prox. Width. Mid. Width. Distal Width. Length. Prox. Width. Mid. Width. Distal Width. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. Enfield 215 81 46 96 490 134 44 71 286 106 43 120 Kapua 216 76 46 102 483 140 46 66 279 102 43 119 Glenmark 210 64 43 97 463 123 40 64 263 99 38 99 Meionornis Didinus. Metatarsus. Tibia. Femur. — Length. Prox. Width. Mid. Width. Distal Width. Length. Prox. Width. Mid. Width. Distal Width. Length. Prox. Width. Mid. Width. Distal Width. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. Enfield 190 68 38 86 400 109 37 58 240 86 35 95 Kapua 190 68 38 87 380 108 35 56 241 86 35 99 Glenmark 184 69 38 81 393 109 37 47 254 92 36 94 On the supposition, therefore, that the three deposits of bones are of the relative ages here put down, we find that during the interval M. casuarinus became larger, especially in the tibia and femur. In M. didinus, on the contrary, the metatarsus and tibia remained practically the same,* The Kapua birds, however, had a smaller tibia. while the femur got smaller. The two, therefore, differentiated

from an intermediate ancestor. The relative numbers of the two species were as follow: At Glenmark M. casuarinus was. four times as numerous as M. didinus; at Kapua it was four and a half times as numerous; while at Enfield M. didinus: was nearly twice as numerous as M. casuarinus, so that M. casuarinus decreased and M. didinus increased, relatively, between the dates of Glenmark and Enfield. This is only advanced as a suggestion for other collectors, to follow up. It may prove to be wrong, or it may lead to observations which will establish the direction of development, of the moas. Leg Bones Fbom Glenmark. Meionornis. Diagrim of the Two Principal Measurements, Length and Mid. Width of Shaft, in Inches. — Inches. 2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 Metatarsus. Femur. Tibia. 19.5 1a 2a 19.0 3a 2a 2a 1a 18.5 5a 12a 15a 2a 18.0 6a 17a 6a 17.5 1a 4a 12a 5a 17.0 1a 6a 1a 16.5 1b 16.0 6b 15.5 2b 6b 2b 15 0 1b 1b 1b 1b 14.5 1b 2b 14.0 1b 2b 12.0 11 5 1 11.0 2 4 18 6 10.5 2 2 15 20 4 10.0 3 5 11 2 9.5 9.0 2 1 8.5 5 15 11 8.0 11 19 17 6 7.5 5 5 7 3 7.0 4 7 6 6.5 1 1 2 a. M. casuarinus. b. M. didinus.