360 



U. S p. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



The genus Chimaera includes, so far, two species, one in the Atlantic, the other in the Pacific 

 ocean. The Atlantic species is exclusively an Arctic fish, whilst that of the Pacific seems to be 

 limited to the temperate zone. 



A similar instance occurs in regard to the species of Callorhynchus ; one being an inhabitant 

 of the Antarctic, the other of the Austral temperate zone. 



CHIMAERA COLLI PI, Benn. 



Spec. Char. — Head constituting about the sixth of the total length. First dorsal fin sub-triangular; the upper margin, 

 which is directed posteriorly, being crescent shaped, wliilst the posterior margin, properly so to be called, is horizontal and 

 parallel with the back, to which it is united by a thin membrane. Second dorsal quite low and elongated, its origin being 

 nearly opposite the insertion of the vcntrals, which is nearly halfway between the apex of the snout and the origin of the caudal 

 fin. Its upper margin is undulating. Either lobe of the caudal tapering regularly away towards the tip of the tail, the lower 

 lobe extending somewhat further back. Skin perfectly smooth ; brownish above ; dull white beneath ; the back and sides 

 exhibiting numerous dull wliite rounded spots, variable in size. 



St.v. — Chimaera colliei, Benn. in Zool. Betchey'sWoj. to the Pacif. 1839, 71., Plate xxiii, figs. 1 and 2. — Richards. Faun. 

 Bor. Amer. Ill, 183C, 285. 

 Elcphant-fish, Vancouver. 

 Skooma, Indians of Oregon. 



The specimens of this species which we have had an opportunity of examining are all of the 

 female sex. The male is figured and described in "The Zoology of Captain Beechey's Voyage 

 to the Pacific and Behring's Strait," as quoted above. 



The body is quite compressed, deepest anteriorly and tapering rajjidly away posteriorly 

 towards the acute and thread-like extremity of the caudal region. The gill apertures extend 

 from tlio upper edge of the base of the pectorals downwards and forwards, being separated 

 under the throat by a rather wide isthmus. We regret that the state of keeping of the speci- 

 mens will not allow a minute descrij^tion to be drawn of the structure of the nostrils in con- 

 nection with the upper or anterior lip. A similar structure is so seldom met with in this class 

 of fish that whenever it exists anywhere it cannot but excite the curiosity of the naturalist. 



The spine at the anterior margin of the dorsal fin is very finely serrated upon the upper half 

 of its posterior aspect, which is flattened, either angle being serrated ; the anterior aspect of 

 the spine is convex and keeled. 



The ventrals being free from the appendages which the male is provided with, are propor- 

 tionally larger and broader, posteriorly rounded off. 



The skin is perfectly smooth all over the head and body. The coloration in the female sex is 

 similar to that of the male. 



List of ftpedmens. 



