Art. XXIII.—Notes on the Anatomy of Regalecus pacificus, von Haast.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 11, 1878, Page 269

Art. XXIII.—Notes on the Anatomy of Regalecus pacificus, von Haast. By Llewellyn Powell, M.D., F.L.S. [Read before the Philosophical Institute of Canterbury, 21st February, 1878.] Dr. Haast, in the description of Regalecus pacificus, * Trans. N.Z. Inst. X., 246–250, pl. vii. speaks of the silvery, or rather, to my eye, steely coating which contributes so greatly to the beauty of this splendid fish. It is impossible to reproduce it either in a drawing or to perpetuate it by any mode of preservation, as it is detached by the slightest touch, leaving a slimy, silvery patch on the finger. This coating has been described as consisting of minute scales by one observer, and by another as scales resembling those on a butterfly's wing. Such is not, however, the case. It is evidently a secretion similar to the slimy mucus which many other fishes secrete so copiously. The microscope resolves the steely layer into myriads of exceedingly minute crystalline needles, or elongated tabular prisms with oblique ends. The largest have a length of 1/160 inch by 1/3000 inch in breadth. These crystals show a beautiful metallic lustre, are not perishable, do not polarize light, are immediately dissolved in liq. potass., but are insoluble in strong acetic acid. I cannot ascertain the nature of the silvery coating found in the swim-bladder of certain fishes, such as Atherina, which was formerly used in the manufacture of artificial pearls. It is not improbably of a similar nature. The scales of the lateral line are peculiarly formed, being very long in proportion to their breadth. Their length slightly exceeds ½ inch, while their breadth does not exceed 1/25 inch; one extremity is slightly expanded or spoon-shaped, the other extremity contracting abruptly to a point which articulates firmly with the dilated extremity of the following scale. These scales appear to me to be tubular, but I cannot be certain of this as they shrivelled in drying. I noted a few points in the internal anatomy. I regret that as daylight was closing, and it was necessary from the extremely soft and watery nature of the integument and the flesh to use despatch in order to save the skin in good condition, I was unable to make a more thorough examination of this interesting fish. The gullet terminated at 2ft. 7in. from the snout in a remarkably elongated muscular stomach, prolonged backward as a kind of cæcum to a length of 4ft. and about 2in., extending 2ft. 7in. beyond the vent in a diverticulum from the peritoneal cavity, and becoming narrower and more and more attenuated until it becomes so exceedingly thin and delicate that, with the utmost care in dissection, the extremity was torn and imperfect. The pylorus was seated immediately by the side of the cardiac orifice, being provided with a strong muscular ring, the duodesma, if one may so

speak of the commencement of the intestine, passed directly forwards, plunged immediately into a cylindrical mass of densely packed pyloric pancreatic cæca. These were short, adherent to one another, and so closely massed that the intestine appeared to have no proper wall, appearing more like a broad glandular duct; on cutting into the pancreatic mass, a white chylous fluid exuded abundantly. The glandular mass was 15in. long by more than 3in. broad. At its extremity the thin-walled intestine emerged from the pancreatic mass and turned abruptly backwards, passing without any convolution to the vent. It was full of a gruelly fluid. The stomach exhibited, in its anterior part, strong longitudinal muscular bundles becoming more and more attenuated as they proceeded backwards. It was empty, being merely coated with a layer of mucus, stained of a pinkish hue, with dark red particles here and there. A microscopic examination of this mucus made with the object of determining the nature of the food of this deep-sea fish, discovered myriads of minute conical calcareous bodies, some of them perforated longitudinally, having a very uniform size of about 1/375 inch by 1/1600 inch broad at the base. I do not know what these may be, but am inclined to think that they are the cutaneous species of some echinoderm. The fish was a female, the ova exceedingly minute and undeveloped. A single oviduct, divided 12 inches anteriorly to the vent into two cylindrical ovaries, these ran forward to a point 17 inches posteriorly to the snout, the right being somewhat smaller than the left, they each terminated in a strong suspensary ligament. The large liver, of a most beautiful vivid orange tint, weighed 41b. 12½oz. It was cleft into two longitudinal lobes posteriorly; there was also some minor lobation, one smaller lobe overlapping the large gall bladder which was full of dirty watery fluid. The liver overlapped the pyloric mass which was entered by the ductus choledocus. The kidneys had the usual situation and appearance; their length was 2ft. 6in. There was no swim-bladder, and of the dorsal bladders spoken of by Mr. Travers I need hardly say there was no trace. It is evident that the curious spaces left by the detachment of the strong longitudinal intermuscular septa were mistaken for bladders by that gentleman. The skeleton consisted of the softest cartilage; it would have been a matter of the greatest difficulty to isolate and preserve it.