68 DISCOVERY REPORTS 



jaw Strongly projecting; maxillary extending to below anterior margin of eye. Upper 

 lateral line extending from the gill-opening to about the vertical of the origin of the 

 dorsal, lower lateral line from below the extremity of the upper to the base of the 

 caudal fin, running along the middle of the caudal region. Dorsal 28-30. Anal (22) 

 24-26. Pectoral with 21 or 22 rays, truncated, J as long as head; pelvics much shorter, 

 not nearly reaching vent. Caudal truncate. Brownish-olive, the lower parts whitish ; 

 large dark spots on head and body; fins dusky. 



Fig. 42. Gymnodraco acuticeps. x \. 



Hab. Wilhelm Land ; South Victoria Land. 



The types of the species, 5 specimens up to 300 mm. in total length, are from Cape 

 Adare, 7 to 14 metres: two of these (200 and 300 mm.) are in the collection of the 

 British Museum. The ' Gauss ' obtained a further example, 200 mm. long, from the 

 Winter Quarters of the expedition in Wilhelm Land. 



Family CHAENICHTHYIDAE 



Body naked. Snout produced and depressed, spatulate. Mouth non-protractile; 

 palatine in great part ligamentous; pterygoid slender; no mesopterygoid. Gill-mem- 

 branes very narrowly united to isthmus or forming a fold across it ; operculum usually 

 with radiating ridges ending in simple or branched spines. Spinous dorsal fin present. 

 Ribs not ossified. 



Nine genera, all of which occur in, and eight of which are confined to, the Antarctic 



Zone. 



Key to the Genera 



I. Middle rays of pelvic fin longest. 

 A. Lateral line without bony plates. 



I. Spinous dorsal of 8 to 15 spines; operculum with at least 3 spines. 

 a. Two lateral lines (upper and middle); dorsal fins subcontinuous. 



a. Dorsal IX-X, 32-40; anal 31-39; no rostral spine; gill-rakers short, but well- 

 developed ... ... I- Champsocephalus. 



p. Dorsal (IX) XII-XV, 26-31 ; anal 24-27; a rostral spine; gill-rakers vestigial 

 or absent 2. Pagetopsis. 



