NATURAL SCIENCES OF PHILADELPHIA. 199 



Caudal fin convex behind. 



Pectoral fins pointed. 



Ventral fins subjugular, inserted obliquely, with its. rays approximated, and 

 its innermost attached to the breast by a membrane. 



The lower pharyngeal bones are entirely separated, compressed and laminar, 

 with the body emarginated below and the posterior processes directed up- 

 wards, attenuated towards their ends ; with the teeth pauciserial ; of the inner 

 row slender, elongated and acute, curved outwards in front and erect behind; 

 of the outer much smaller, but similar in form. Upper pharyngeals three on 

 each side laminar, each with a row of large, slender, curved teeth. 



The branchial arches have compressed, pointed rakers, progressively de- 

 creasing in length from the first to the fourth arch, on which last they are 

 ehort and triangular ; each armed with small, slender teeth on their internal 

 margins. 



Metoponops is readily distinguishable by the characters above given, espe- 

 cially the prominence of the interorbital ridge and the consequent oblique po- 

 sition on the forehead of the upper eye, whose line of vision is upwards ; the 

 scaly channel of the ridge itself; straight lateral line ; dentition, and the form 

 of the lower pharyngeal bones, especially the paraboloid emargination below 

 in front. It is apparently as closely related to its cohabitant of California, 

 Orlhopsetta, as any other, but that genus is at once distinguished by its com- 

 pressed head and little prominent, narrow interorbital ridge. 



Metoponops Cooperi Gill. 



The height of the body is contained about three times in the total length; 

 the head about four times, and the caudal six times and a half. The longitu- 

 dinal diameter of either orbit equals about a third of the head's length. The 

 snout is rhomboid, decurVed in front, and its length from the lower orbit to 

 the symphisis equals about a fifth of the head's length. The supramaxillary 

 ends under the front of the pupil, and from the symphisis to its end enters 

 twice in the distance between the chin and preopercular margin. The greatest 

 height of the dorsal equals the length of the upper jaw, as well as does that 

 of the anal. The pectoral fin equals about a sixth of the total length. 



D. 89. A. VI. P. 13. 



The color is uniform brownish. 



A single adult specimen of this species is in the collection formed by the 

 Californian Geological Survey, of which Prof. Whitney is the superintendent, 

 and was obtained by Dr. Cooper, the naturalist of the Snrvey, at Santa Bar- 

 bara, in May, 1863. This specimen is in poor condition, having been appa- 

 rently obtained only after exposure for some time to the sun ; the fins have 

 been dried, and the pectorals and ventrals are more or less broken, especially 

 the latter, while the abdomen is much injured. I am consequenily compelled 

 to omit some desirable details. The species itself is a very interesting one, 

 and I give myself the pleasure of dedicating it to my friend, Dr. Cooper. 



On the Afiinities of several doubtful BRITISH FISHES. 



BY THEODORE GILL. 



Among the few still uncertain species of British fishes, none are involved 

 in greater obscurity than those presented under the name of Ophidium imberbe 

 by Pennant and Montague, and those referred by Hoy to the Linmean Trichi- 

 urus leplurus. A detailed investigation into the literature and history of the 

 former has enabled me to demonstrate its relations, and the discovery of a 

 recent type in the Caribbean Sea permits me to at least suggest the affini- 

 ties of the latter,* concerning which I had long been perplexed. These con- 



* See Proceed. Acad. ?<at. Sci. Phila., 1863, p. 228. 



1864.] 



