54 DISCOVERY REPORTS 



b. Three lateral lines (at least in adult), a long upper one, a short middle one on 

 side of caudal peduncle, and a short lower one above base of posterior part of 

 anal fin; snout broader, not more than i\ times as long as eye; dorsal with 30 

 to 37 rays, anterior part of fin forming a fairly distinct lobe; caudal rounded 



or subtruncate 3. Racovitzia. 



B. Body quadrangular, with a series of V-shaped, serrated bony plates at each angle, each 

 plate with a backwardly directed spine; a single short lateral line, ending below anterior 

 part of dorsal 4. Prionodraco 



II. Body naked. 



A. Snout produced, spatulate; teeth in villiform bands, without canines; operculum 

 with divergent ridges, ending in spinous points. 



1. Upper lateral line ending below posterior part of dorsal; dorsal with 61 to 66 rays. 



5. Cygnodraco. 



2. Upper lateral line extending beyond end of dorsal; dorsal with 42 to 46 rays. 



6. Parachaenichthys. 



B. Snout not spatulate; canine teeth present in one or both of the jaws; operculum 

 with a strong spine terminating in a hooked process. 



1 . Head and anterior part of body only slightly depressed ; no canine teeth in lower 

 jaw; mouth protractile; three lateral lines 7. Psilodraco. 



2. Head and anterior part of body distinctly depressed; strong canine teeth near 

 symphysis of mandibles, exposed in front of snout; mouth not protractile; two 

 lateral lines 8. Gymnodraco. 



Genus BATHYDRACO 



Bathydraco, Giinther, 1878, Ann. Mag. Nat. Hist., (5) 11, p. 18; Regan, 1913, Trans. R. Soc. 

 Edinburgh, xlix, p. 281. Type Bathydraco antarcticus, Giinther. 



Body scaly; a single lateral line, running to or towards middle of base of caudal. 

 Snout produced, spatulate; jaws with bands of small villiform teeth. Operculum with 

 upper edge concave, but without hooked branch posteriorly ; gill-rakers well-developed 

 and of moderate length; gill-membranes free from the isthmus, but slightly united 

 anteriorly ; 7 branchiostegals. 



Five species. 



Deep water near the coasts of the Antarctic Continent. 



Key to the Species 

 I. Depth 9 to 10 in length; eye 3! to 5 in head; dorsal 34-38, anal 29-31 ; sides of head more 

 or less scaly. 

 A. 1 1 to 16 gill-rakers on lower part of anterior arch; lateral line complete. 



1. Only the upper half of operculum scaly; cheek completely scaled; 16 gill-rakers 

 on lower part of anterior arch; about 140 scales in a longitudinal series. 



I . antarcticus. 



2. Operculum nearly completely scaly; cheek naked below suborbitals; 11 gill-rakers 



on lower part of anterior arch; about 125 scales in a longitudinal series. 2. marri. 



3. A small patch of scales on upper part of operculum; cheek naked below sub- 

 orbitals; II gill- rakers on lower part of anterior arch; about 90 scales in a longi- 

 tudinal series ... 3- macrolepis. 



