238 DEEP SEA FISHES. 



wide, nearly vertical. Teeth small, acicular, on jaws, palatines, and vomer.' 

 Forehead with a ridge at each side. Preopercular and scapular spines. 

 A small compressed blade in front of the dorsal fin. An abdominal keel 

 composed of the united lower edges of imbricated plates each of which 

 covers a lantern. Four gills, fourth small ; rakers long, numerous. 

 Pseudobranchia^. 



Two species known ; P. spinosus Glint, secured by the " Challenger" 

 between the Philippines and Borneo, in 250 fathoms, and P. latcrnatus 

 n. sp., taken by the " Blake " off Barbados, in 221 fathoms. 



Polyipnus laternatus sp. n. 



Polyipnus spinosus G. B., 1896, Oo. Icli., PI. XXXIX., fig. It8. 



Br. r. 9 ; D. 14 ; A. 9 4- 7 ; V. 7 ; P. 15; LI. 31. 



Between P. latenudtis and P. spinosus there is not a great deal of differ- 

 enee in shape. The outline of the lower surflice is but little indented between 

 the ventrals and the anal. The length of the head is nearly one third of 

 the total length, or a little more than half of the greatest depth ; the crown 

 has a low sharp ridge at each side. Snout short, blunt. Mouth of 

 moderate size, nearly vertical, more than half of its upper border formed 

 by tlie intermaxillaries. Teeth minute, in single series on the jaws, on the 

 anterior ends of the palatines, and at each side of the vomer ; the last series 

 curving forward toward the palatine. Gill rakers slender, more than half 

 as long as the eye, eight plus fourteen on the forward edge of the first 

 arch. Pseudobranchiaj well developed. Abdominal keel of ten pairs of 

 plates. Clavicidar and ventral angles short. Scapular spines more than 

 one third as long as the eye, directed backward. The blade in front of the 

 dorsal is a small, low, compressed ridge which precedes two ridges, with a 

 trough between them, that end in a pair of backward upward and laterally 

 directed spines immediately in front of the fin. The blade forms a sharp 

 angle in front of the trough. Pectoral fins elongate, reaching behind the 

 bases of the ventrals. Caudal deep ; caudal pedicel deep and strong; 

 caudal section not abruptly constricted at the body. 



The lanterns are well developed in both disks and reflectors; they are 

 placed as follows : one on the forehead, one in front of and one behind the 

 eye, two behind the end of the maxillary — the larger below the orbit, 

 six in the branchiostegal series, six on the isthmus, ten along the edge of 



