PowELL.—On Anatomy of Regalecus pacificus. 269 
Art, XXIII, — Notes on the Anatomy of Regalecus pacificus, von Haast. 
By LunEgwELLyN Powerr, M.D., F.L.S. 
[Read before the Philosophical Institute of Canterbury, 21st February, 1878.] 
Dr. Haast, in the description of Regalecus pacificus,* speaks of the silvery, 
or rather, to my eye, steely coating which contributes so greatiy 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 41, inch by 4454 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 } inch, while 
their breadth does not exceed j inch; one extremity is slightly expanded 
or spoon-shaped, the other duran uude abruptly to a point which 
articulates firmly with the dilated extremity of the following scale. These 
seales appear to me to be tubular, but I cannot be ceriain 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 gulle& terminated at 2ft. Tin. from the snout in a remarkably 
elongated muscular stomach, prolonged backward as a kind of cecum 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 æ had : 
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