35 



Dr. Knox having undertaken the dissection, and minute anatomical 

 description of the specimen, has furnished the following valuable notes ; 

 together with the preparations they refer to, which are deposited in the 

 Colonial Museum. 



Anatomical Observations on Ophisurus Nov^e Zelandi^e, (Hector.) By 



Dr. Knox. 



The Integuments. 

 The external characters of this fish having been given by Dr. Hector, I 

 shall only make a few remarks on the skin. The specimen having been 

 preserved in strong alcoholic mixture, necessarily altered, not only the 

 colouring, but also the integumentary tissue itself; not a vestige of scales 

 could be observed, and considerable difficulty was found in removing the skin, 

 more especially at the connection of the dorsal and anal fins. Little or no oil 

 appeared to be present, and when dried, the absence of oil became more striking. 

 I found it, viewed as a transparent object, entirely dotted over with minute 

 black spots ; and immediately below the lateral line, a regular series of spots of 

 larger size, and placed at about two lines from each other. These latter I 

 consider glandular orifices ; they are also very distinct on the lip or margin of 

 the upper and lower jaws. On the inner surface of the abdominal aspect of 

 the skin, there extends, from the gill aperture to the anus, a well-developed 

 cutis-muscle, which, by its contraction, will assist in progression, in a similar 

 manner, to the abdominal scutoe in some of the Reptilise (Tuatara, etc.), no 

 doubt required, in consequence of the extremely rudimentary nature of the 

 ribs. 



The Skull— Fig. 4. 



The head of the Ophisurus is at once remarkable for its smallness, and 

 for its high degree of development. The organs of sense, and the dentition, are 

 fully represented. The Ophisurus stands, in this respect, in strong contrast to 

 fishes, in which the head is almost universally, enormously (disproportionally) 

 developed. Even in his closely-allied relation, the eel (Murcena, Linn.), the 

 head continues to hold something like a proportion to the body. It will be 

 seen from the annexed table of weights, that the total weight of the skull is 

 thirty grains, but this is much beyond the true weight of the bones, as the 

 integumentary covering on the right side, was left in sitit, in order to display 

 the position of the nostrils, and the gill coverings, and thus the bones in the 

 skeleton of the head would certainly not weigh more than fifteen or twenty 

 grains. 



The smallness, added to the non-development of the osseous centres of 

 ossification, render any attempt to describe the separate bones of the skull, 

 impossible. The view of the skull from above (Fig. 5) exhibits, very beautifully, 

 the fact (although not very long ago, the theory) of the head being merely a 

 continuation of specialized vertebrae ; it does not signify whether the number 

 be 3, 7, or 7 times 7. 



The upper jaw (Fig. 6), after gradually narrowing, expands into a semi-oval 

 surface, convex above, concave on its dentar or buccal aspect. The rami of 

 the lower jaw (Fig. 7) are proportionally long, and quite straight, terminating 

 with a symphysis peculiarly formed, so as to receive an azygos tooth in the 

 upper jaw. The opercula are well developed. 



The lower jaw (Fig. 7) is formed of two perfectly straight rami, uniting at 

 the symphysis by cartilage, and articulating with the articular process of the 

 temporal bones in the usual manner ; the temporal fossae are large, affording 

 ample space for the attachment of strong temporal muscles, no doubt 

 occasionally required when an unusually large crawfish is selected for a feed. 



G 



