105 



Key to the Indian genera of the family Macruridae. 



I. Snout projecting beyond the mouth : rays of the anal fin better 

 developed than those of the second dorsal : gill-rakers on the outer 

 side of the first branchial arch tuberculiforru ... ... Macrurus. 



II. Snout not projecting beyond the mouth : rays of the second dorsal 

 fin better developed than those of the anal : gill-rakers on the outer 

 side of the first branchial arch long and setiform ... ... Bathtgadus. 



Macrurus, Bloch, Giinther. 



Macrurus, Giinther, Challenger Deep-Sea Fishes, pp. 122-124. 



Macrurus, Coelorhynchus, Coryphaenoid.es, Hymenocephalus, Lionurus, Trachonurus, Cetonurus, Chalinura, 

 Optonurus, Malacocephalus, Nematonurus, Moseleya, Abyssicola, Goode and Bean, Oceanic Ichthyology, pp. 390-417. 



Malacocephalus, Moseleya, Nematonurus, Albatrossia, Bogoslovius, Chalinura, Coryphaenoides, Hymenocephalus, 

 Macrourus, Coelorhynchus, Trachonurus, Lionurus, Jordan and Evermann, Fishes N. America, pp. 2569-2592. 



Head short and thick with the nmciferous cavities well developed ; tail long 

 and tapering. 



The snout usually projects well beyond the mouth, which may be either 

 quite inferior or lateral and subterminal. Teeth in the jaws only. A barbel at 

 the symphysis of the lower jaw. 



Gill-openings wide, the gill-membranes slightly united in front. The first 

 branchial arch is broadly connected by membrane with the outer wall of the gill- 

 chamber, so that the slit between that arch and the gill-cover is very much 

 narrower than the other branchial clefts. The gill-rakers on the outer side of the 

 first branchial arch are mere scabrous tubercles. 



Scales either strongly and typically ctenoid or, more rarely, cycloid. No 

 scaleless fossa on the side of the nape. 



Second dorsal fin separated from the first by an interval ; its rays, or at least 

 its anterior rays, are more or less rudimentary. Anal rays much better develop- 

 ed than those of the second dorsal. Ventrals arising below, or slightly in 

 advance of, the pectorals. 



Key to the Indian subgenera of Macrurus (adapted from Dr. Giinther). 



I. Villiform teeth iu bands in both jaws : scales imbricate and spini- 

 gerous : — 



1. Dorsal spine serrated : mouth inferior ... ... Macrorus. 



2. Dorsal spine smooth : — 



i. Mouth inferior ; the infraorbital region divided 

 into a vertical and a subhorizontal portion by a 

 longitudinal ridge ... ... ... Coelorhynchus. 



ii. Mouth wide, in the ordinary lateral position ... Mystaconurus. 

 II. Teeth in two series in the upper jaw and in a single series in the 

 lower jaw. [Dorsal spine smooth : mouth lateral : scales imbricate 

 and spiuigerous] ... ... ... ... .,. Malacocephalus. 



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