FISH. 149 



Form. — Body thickish, the greatest depth and thickness nearly equal, the former about one-twenty- 

 fifth of the whole length. From the head to the vent heptangular ; tail quadrangular : all the 

 angles sharp and distinctly marked. The middle lateral ridges in the heptangular portion pass 

 downwards at their extremities to terminate at the vent. Sixteen transverse plates before the 

 dorsal : only fifty-two in the whole length. Head short, about one-eleventh of the entire 

 length, not more compressed than the body. Crown not much elevated, but with distinct 

 occipital and nuchal ridges. Orbits rising in ridges above the eyes, the interocular space being 

 hollowed out : also a ridge commencing between the eyes, and passing forwards along the base 

 of the snout, but not reaching to its extremity. Snout itself very short, its length only one- 

 third the entire length of the head, narrower than the head vertically, nearly cylindrical, the 

 tip slightly recurved. A few very short minute filamentous threads scattered about the head, 

 more particularly one over each eye. 



Dorsal placed much as in the last species, and terminating a little before the middle ; the 

 rays delicate and not easily counted, about twenty. Vent beneath the commencement of the 

 dorsal. No anal distinguishable even under a lens. Pectorals very small. Caudal moderately 

 distinct. 



Colour. — Grey : a spot on the gill-cover, and the belly, dusky. The carinas which form the edges 

 of the under surface of the body are darker still, and shew a fine dark line on each side 

 extending to the caudal. 

 Habitat, Bahia Blanca, Northern Patagonia. 



Apparently another new species of this genus, taken by Mr. Darwin at 



Bahia, and, like the last, well-marked ; especially by the short filaments above 



the eyes, which I am not aware occur in any other known species. 



