598 Bulletin 47, United States National Museum. 



median or posterior ; adipose fin small. Pseudobranchise well developed. 

 No air bladder. Deep-sea fishes ; two genera and two species known, 

 a. Post-temporal of peculiar form, partly naked; stomach very distensible. OMOSUDIS, 285. 



285. OMOSUDIS, Giinther. 



Omosudis, GUNTHER, Challenger Report, xxn, 201, 1887, (lowii). 



Body oblong, compressed ; head compressed, naked ; snout of mod- 

 erate length ; cleft of mouth very wide ; premaxillary and maxillary 

 bones slender, the former with a series of very small teeth of equal size, 

 only one or two anterior ones being somewhat enlarged ; the lower jaw, 

 the vomer, and palatine bones with a few very large and lanceolate teeth. 

 Lower jaw broad, and, like the rest of the head, formed of very thin bone. 

 The supraclavicle and postclavicles form a long rod extending from occiput 

 on each side downward to the abdomen, and partly free, not covered by 

 skin. Ventral fins inserted far behind the pectorals, below the origin of 

 the dorsal ; dorsal fin behind the middle of the length of the body; adi- 

 pose fin very small ; anal fin long. Stomach very distensible. Branchios- 

 tegals 8 ; pseudobranchise well developed ; gills 4, with broad gill laminae 

 and very short gill rakers. (//of , shoulder ; Sudis.) 



894. OMOSUDIS LOWII, GUnther. 



Head 3| ; depth 5 ; eye 3. Head strongly compressed, with rather flat 

 upper surface ; snout somewhat pointed, rather longer than eye. Bones 

 of head extremely thin, the opercle being smaller than the subopercle, 

 and separated by two or three ridges. Infraorbital ring nearly membran- 

 aceous. Preoperculum terminating below in a forked point. Cleft of 

 mouth extending backward to angle of preoperculum. Dentition truly 

 formidable for so small a fish ; the longest tooth is one anteriorly on the 

 side of the mandible ; in the British Museum specimens, only one is 

 present either on the right or left of the jaw ; its length nearly of 

 that of the head ; the next largest are those on the palate, where there 

 are two on each side, besides several smaller ones ; smaller teeth are also 

 implanted on the hinder part of the dentary bone ; all the large teeth can 

 be laid backward. A semicircular, scale-like, osseous lamella of extreme 

 thinness covers lower part of cheek, it is marked by very shallow, con- 

 centric striae. The singular bone which supports the side of the anterior 

 part of the abdomen is sty-liform, slightly curved backward ; it starts 

 from the top of the occiput and descend toward the median line of the 

 abdomen, which it reaches behind the pectoral fin ; it is composed of the 

 two-pronged supraclavicle, which is fixed by ligaments to the occiput, and 

 of three slender, needle-shaped postclavicles ; the uppermost postclavicle 

 is suspended by ligaments from the supraclavicle, as is also the clavicle ; 

 the rod lies immediately below the thin integument, and its lower portion 

 is quite free. Dorsal fin inserted midway between root of caudal and eye, 

 and composed of very feeble rays ; the anal commences at some distance 

 behind the dorsal and terminates not very far from the caudal ; caudal 

 fin small, with a considerable number of basal rays above and below ; pec- 

 toral fins quite at the lower side of the body ; ventral fins very small and 



