REPORT ON THE PELAGIC FISHES. 41 



the anal is continued as an even broad fringe to the vent. A dark shaded portion of 

 this anal fin seems to indicate also, in this specimen, the presence of a permanent anal, 

 the position of which corresponds closely to that of a similar structure in our first and in 

 the following specimen. The vent is placed far forwards, at a distance from the head 

 less than the length of the latter. Abdominal organs visible through the thin integu- 

 ment of the walls of the abdomen. Pectoral present. Eye of moderate size. Snout 

 produced, with wide cleft of the mouth, which was armed with pointed teeth. This 

 specimen was 1;^ inches or about 32 mm. long ; it was not preserved, nor is it known 

 where it was caught. 



The fourth specimen known of Prymnothonus, the third of the Challenger collection, 

 is 44 mm. long, and was obtained on February 26, 1874, south-west of Kerguelen 

 Island, in lat. 62° 26' S., long. 95° 44' E., in the dredge, which had reached the depth of 

 1975 fathoms. However, it is more probable that it entered the dredge near the 

 surface, like the other specimens. The head and body are slender (PI. V. fig. D), the 

 greatest depth of the former being only 2 mm., and that of the middle of the body 

 1^ mm. The body is compressed, of a whitish colour, no muscular segmentation showing 

 through the integuments. Only the tough wide sheath of the notochord remains, without 

 a trace of ossification. Many of the cranial bones are distinctly ossified. Tail homocercal, 

 with a well-formed bilobed caudal fin ; at a distance of 6 mm. in front of the caudal a 

 rayed anal fin commences, which, however, shows rays in the middle only, passing into 

 the remains of the embryonic fin anteriorly and posteriorly ; opposite to this anal, in 

 front of the caudal, a dorsal fin is represented by a short strip of the embryonic fin- 

 fringe. 



The head is 7^ mm. long, with a prolonged, straight, pointed snout (4 mm.). 

 The cleft of the mouth extends backwards to the eye ; jaws armed with widely set, strong, 

 acute teeth, unequal in size. Eye large, projecting. Pectoral fin small, but I have been 

 unable to distinguish ventral fins or the position of the vent. The abdominal cavity 

 seems to have been as long as the head. As in the other specimens, the dorsal and 

 ventral muscles have not yet met in the median line of the side of the abdomen, so that 

 the abdominal organs are covered by the integument only, through which the outlines of 

 the stomach are clearly visible. 



I have no doubt that all these specimens represent larval conditions of fishes be- 

 longing to Paralepis or Sudis, or of genera allied to them. That they all are stages of 

 development of the same generic type of fishes is very improbable, but the second and 

 third specimens may well be considered to be the same type, which provisionally may be 

 designated by the name proposed for it by Richardson. 



(ZOOL. CHALL. EXP.— PART LXXVIII. — 1889.) lui G 



