177 

 141. Platytroctes apus, Gimther. 



Platytroctes apus, Giinther, Ann. Mag. Nat. Hiet. 1878, II. p. 249, and Challenger Deep-Sea Fishes, p. 229, pi. 

 lviii. fig. A: Alcock, Ann. Mag. Nat. Hist. (6) VI. 1890, p. 307: Goode and Bean, Oceanic Ichthyology, p. 46, 

 fig. 53 : Jordan and Evermann, Fishes of N. Amer., p. 458. 



D. 18. A. 17. P. 20. L. lat. circ. 100. 



Length of the head two-sevenths, greatest height of the body, at its middle, 

 rather more than a third the total length without the caudal. More than half 

 of this height, however, is contributed by simple dorsal and ventral folds of skin 

 into which neither muscles nor viscera enter. 



The snout is shorter than the eye, which is a third or more the length of 

 the head and almost enters the dorsal profile. Nostrils large, superior, nearer 

 to the edge of the snout than to the eye. 



The narrow triangular interorbital space and the occiput are sharply con- 

 cave, the concavity being bordered on each side by a mucous canal with large 

 pores. A similar mucous canal with pores runs along the preorbital, and another 

 one along the free edge of the preopercle. 



Mouth rather short but broad, the lower jaw projecting when the mouth is 

 open. The maxilla, which is a broad petal-shaped bone, reaches to or a little 

 beyond the anterior edge of the eye. The limbs of the mandible make a curious 

 boat-shaped bone. A single series of small even teeth in the premaxilla and 

 maxilla and in the front half of the mandible : a small tooth on either side of the 

 head of the vomer. 



Gill-laminse very short : gill-rakers on the first branchial arch long, ex- 

 tremely numerous and close-set. 



The clavicles project freely at their symphysis as a pair of spikes separated 

 only at tip. 



The vent is much nearer to the root of the caudal than to the gill-opening : 

 the dorsal fin begins immediately above it and the anal immediately behind 

 it. 



Pectoral fin short, about half as long as the eye, its base nearly horizontal. 



Scales small, cycloid : those near the dorsal and ventral profiles, and many 

 of the others, have a keel, like the scales of many snakes. 



Colours in spirit : brown ; head, pectoral region, vent, and edges of caudal 

 peduncle black. Length six inches. 



Arabian Sea, in the neighbourhood of the Laccadive banks, 740 fathoms. 



Regd. No. 12868. 



Distribution : Mid- Atlantic ; Arabian Sea. 

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