present in membranous pouches on strongly enlarged scales. 

 Dorsal behind ventrals, short ; a second long rudimentary dorsal 

 may be present. Anal occupying the entire length of the tail. 

 Pectorals inserted high up ; ventrals not very far back, they may 

 be united by membrane. Gillopenings wide, gillmembranes 

 entirely separate, with numerous branchiostegals. Praeoperculum 

 rudimentary and detached from suspensorium, suboperculum 

 enlarged, interoperculum membranous, operculum normally 

 connected. No pseudobranchiae. Ovaries lamellated, open, the 

 ova falling into the abdominal cavity. 



Deep sea fishes of worldwide distribution between about the 

 40 N.Lat. and 46 S.Lat. 



Key to the indo-aust ralian genera of 

 Halosauridae. 



1. Vertex covered with scales; scales of lateral line scarcely 



enlarged, without luminous organs Halosatirus p. 2. 



2. Vertex scaleless; scales of lateral line much enlarged, 



with luminous organs Halosauropsis p. 4. 



r. Halosaurus Johnson. 



(I. Y. JOHNSON, Proc. Zool. Soc. London 1863, p. 406). 

 Halosaurichthys Alcock Ann. Mag. Nat. Hist. (6) IV. 1889, p. 454 p. p. 



Head with scales on cheeks, temples, vertex and in indo- 

 pacific species also on snout. Scales of lateral line only slightly 

 enlarged and without luminous organs. Head without angular 

 ridges. The ventrals may be more or less united by membrane 

 or totally free. A low median fold on the posterior dorsal 

 part of the tail, covered by enlarged and elongated scales, 

 may individually be present or absent. 



For distribution see that of the family. 



i. Halosaurus carinicauda (Ale.) [Fig. i, p. 3]. 



Halosaurichthys carinicauda Alcock, Ann. Mag. Nat. Hist. (6) IV. 1889, p. 454. 

 Halosaurichthys carinicauda Goode & Bean, Oceanic Ichthyology 1895, p. 136, 517. 

 Halosaurus carinicauda Alcock, Journ. Asiatic Soc. Bengal LXV. 1896, p. 336. 

 Halosaurus carinicauda Alcock, Descript. Catal. Indian Deep-Sea Fishes 1899, 



p. 187. 

 <.'-., Halasaur us carifricauda Max Weber, Siboga-Expeditie, Fische 1913,' p. 93- 



5 -.>" .ft"V? 3? I^io ii; V. 1.9; P. 14 15; L.I. ca 60 (between 

 ' tieacl and anus) ; L.t . 1 6 1 7. 



