EEPORT ON THE DEEP-SEA FISHES. 105 



termination of the tail is comparatively broad, the rays starting from the end may be 

 regarded as the caudal portion. All the fin rays are thin and closely set, enveloped in a 

 broad basal membrane, so that it is difficult to ascertain their number without dissection. 

 Origin of the dorsal fin midway between occiput and vent. Anal fin commencing 

 immediately behind the vent. Pectoral fin, with broad fleshy base, as long as the post- 

 orbital portion of the head. The ventrals do not extend so far backwards as the 

 pectorals, and the distance between their root and the vent is much more than the 

 length of the head. 



Uniform brown with black fins. 



Habitat. — Off Middle Island, Messier Strait,' Station 306a; depth, 345 fathoms. 

 One specimen, 8 inches long. 



Pteridium (Scopoli). 



Head and body compressed, covered with very small scales, only the upper part of 

 the head and the snout being naked. The body is moderately elongate, the tail but 

 little attenuated. Snout obtuse, not swollen, with the jaws even in front, and with the 

 mouth obliquely ascending. Bones of the head firm, the muciferous canals narrow. 

 Eye small. Operculum with a short spine behind ; praeoperculum with two short 

 projections near the angle. Barbels none. Bands of villiform teeth in the jaws and 

 an open V-shaped band on the vomer ; some slightly enlarged teeth along the inner 

 series of the mandible and on the vomer; palatine teeth none. Vertical fins con- 

 fluent; ventrals close together, reduced to a pair of fine simple filaments, and inserted 

 somewhat behind the isthmus, below the middle of the operculum. Lateral line inter- 

 rupted. Gills four ; pseudobranchise none. Brauchiostegals eight. Pyloric appendages 

 two. 



Only one species is known. 



Ptendium atrum (Risso). 



Very scarce in the Mediterranean, and admitted here for comparison with the allied 

 bathybial genera. Probably it also is an inhabitant of considerable depths, but nothing 

 is known on this point. Having now obtained a specimen 3| inches long, but in a 

 somewhat desiccated condition, I am enabled to correct my former diagnosis,^ which was 

 drawn up from Filippi and Verany's description. The lateral line is rather indistinct, 

 interrupted, and the fact that the ends of the two portions overlap each other, gave rise 

 to the statement that the line was double along a portion of the tail. 



' Fish., vol. iv. p. .375. 



(ZOOL. CHALL. EXP. — PART LVII. — 1886.) Lll 1 i 



