NOTOTHENIIDAE 43 



vent. Caudal slightly emarginate; caudal peduncle about as deep as long. Silvery, 

 back darker ; back and sides powdered with blackish dots ; fins all pale. 



Hab. Circumpolar in the Glacial District (see p. 97). 



The types of the species, up to 165 mm. in total length, are from the ice barrier, 

 Victoria Land, at 78° 35' S. Regan has described and figured several larval and post- 

 larval specimens from the Ross Sea and the coast of Victoria Land, and points out that 

 in these the eye is proportionately smaller than in the adult fish, no doubt because the 

 latter descend to greater depths. He has shown that larval and post-larval examples 

 have been taken not far from the coast and at depths not exceeding 80 metres ; young 

 fish (30 to 35 mm.) in the Ross Sea at a depth of 356 metres. The B.A.N.Z. Antarctic 

 Research Expedition obtained larger young (65 to 82 mm.) in 66° 36-5' S, 141° 44' E, 

 with tow-nets hauled obliquely from o to 11 1 metres, and in 68° 14' S, 70° 11' E, with 

 hand-nets at the surface (the fish being frozen and seen floating past the ship). The 

 'Aurora' obtained many young {c. 70 mm.) in 66° 8' S, 94° 17' E, at a depth of 20 

 metres. Adults have been taken at various localities, and generally at depths ranging 

 from about 150 to 500 metres. A number of specimens have been recorded frozen on 

 the ice barrier or at the surface of the sea, and others have been taken from the stomachs 

 of seals or penguins. 



Family HARPAGIFERIDAE 



Closely related to the Nototheniidae, but with the body naked; two lateral lines, the 

 upper always with tubules, the lower sometimes reduced to a series of pores; gill- 

 membranes broadly united to the isthmus, not forming a fold across it; operculum 

 hooked upwards posteriorly, its upper edge deeply concave. 



Five genera, all occurring in the Antarctic Zone, and one {Harpagifer) extending into 

 the Subantarctic Zone. 



Key to the Genera 

 I. A mental barbel present; opercles not spinate. 



A. Post-temporal not prominent; head not or scarcely broader than deep; interorbital 

 region narrow. 



1. Spinous dorsal fin above base of pectoral ... ... ... i. Artedidraco. 



2. Spinous dorsal fin above operculum ... ... ... ... 2. Dolloidraco. 



B. Upper limb of post-temporal projecting as a prominent curved ridge; spinous dorsal 

 fin above operculum. 



1. Head longer than broad, scarcely broader than deep; interorbital region narrow. 



3. HiSTIODRACO. 



2. Head nearly as broad as long, much broader than deep; interorbital region wide 



or rather wide 4. Pogonophryne. 



II. No mental barbel; operculum and suboperculum each forming a prominent spine. 



5. Harpagifer. 

 Genus ARTEDIDRACO 



Artedidraco, Lonnberg, 1905, Wiss. Ergebn. Schwed. Siidpol.-Exped., v (6), p. 39; Regan, 1913, 

 Trans. R. Soc. Edinburgh, XLix, p. 280. Type Artedidraco skottsbergi, Lonnberg. 



A comparatively short upper lateral line with tubules ; lower lateral line reduced to 

 a series of pores. Head not or scarcely broader than deep ; snout shorter than eye ; 



6-2 



