FISH. 49 
Mr. Darwin obtained one specimen only of this new genus at Chatham 
Island in the Galapagos Archipelago. It is probably not full-sized. 
PRISTIPOMA CANTHARINUM. Jen. 
Puate X. 
P. caruleo-argenteum, operculo nigro-marginato: pinnd dorsali subequal, spinis 
ultimis radiis articulatis paulo brevioribus ; anali spind secundd forti, longitudi- 
naliter striatd, radiis articulatis duodecim: preoperculo rectangulato, margine 
adscendenti, leviter denticulato, basali integro: vertice, buccis, et ossibus opercula- 
ribus, squamatis; rostro ultra nares, suborbitalibus, et mawillis, nudis; squamis 
corporis ciliatis: pinna caudali furcata. 
B. 7; D. 12/15; A. 3/12; C.17, et 4 breviores; P. 20; V. 1/5. 
Lone. unc. 10. lin. 11. 
Form.—Form oblong-oval, much resembling that of the Cantharus griseus. Body compressed, 
with the dorsal line slightly curved ; the profile descending from the nape more obliquely, and 
in a very regular manner. Greatest depth beneath the commencement of the first dorsal, 
contained not quite three times and three quarters in the entire length: head rather less than 
one-fourth of the length. Mouth protractile, but not wide, the commissure not extending to a 
vertical from the anterior angle of the eye; when closed, the maxillary retires beneath the 
suborbital, and only just the extremity remains visible. Jaws equal ; in each a narrow band of 
velutine teeth, the outer row somewhat longer than the others, particularly above, where they 
approach to card. Tongue, palatines, and vomer smooth. Eyes moderate ; their diameter 
rather less than one-fifth of the length of the head; rather nearer the extremity of the snout 
than the posterior margin of the opercle ; the distance between them equalling twice their 
diameter. Two small pores and a fossule beneath the symphysis of the lower jaw, the latter 
very distinct. Preopercle rectangular, the angle somewhat rounded ; the ascending margin 
nearly straight and finely denticulated, but the denticulations hardly continued to the angle, 
and not appearing at all on the basal margin. Opercle with two small flat points, but very 
indistinct and almost lost in the membrane. Suborbitals large, with their lower margins entire. 
Crown, cheeks, and pieces of the gill-cover, covered with small scales; but not the snout in 
advance of the nostrils and eyes, nor suborbitals, nor lower jaw. Suprascapulars marked by a 
large scale, the margin of which is nearly entire. 
Lateral line following the curvature of the back at one-third of the depth ; each scale 
marked with an elevated line without ramifications. A scale taken from above the lateral line 
is of a somewhat rhomboidal form ; the free portion very finely striated, with the margin finely 
H 
