Dr. A. Giinther on new Fishes from Japan. 443 



Family Bathythrissidae. 



Body oblong, with rounded abdomen, covered with cycloid 

 scales ; head naked ; barbels none. Margin of the upper jaw 

 formed by the intermaxillaries mesially, and by the maxil- 

 laries laterally. Opercular apparatus complete. Adipose fin 

 none ; dorsal fin much elongate, many-rayed ; anal fin short. 

 Stomach with a blind sac ; pyloric appendages numerous. 

 Gill-apparatus well developed ; pseudo branchiae ; gill-open- 

 ings wide ; an air-bladder. Ova very small ; ovaries without 

 duct. 



Bathythrissa. 



Body covered with scales of moderate size. Head narrow, 

 oblong, Avitli the muciferous channels much developed. Eye 

 large. Mouth narrow, coregonoid, with bands of minute teeth 

 imbedded in the thick lips ; maxillary with a marginal row of 

 very small teeth. Caudal fin forked, with a dense layer of 

 small scales. Air-bladder with very thick walls, terminating 

 in two short ht is in front, pointed behind. 



Bathythrissa dorsalis. 



B. 6. D. 56. A. 12. V. 9. L. lat. 112. L. transv. 8/13. 

 I Caec. pylor. 14. 



The general aspect of this remarkable fish is that of a much 

 elongate Coregonas^ its greatest depth being one fifth of the 

 length of the body (without caudal). The head is low, elon- 

 gate, one fourth of that length ; the large eye, the diameter of 

 which is rather more than one fourth of the length of the 

 head, occupies nearly the middle of its length, slightly en- 

 croaching upon the upper profile. The width of the intcror- 

 bital space is much less than the diameter of the eye. Snout 

 projecting beyond the mouth as in a Coregonus ; mouth late- 

 rally extending to below the anterior nostril ; the labial fold 

 of the mandible does not extend across the symphysis. Nos- 

 trils close together, separated by a membrane only. The 

 muciferous channel of the infraorl^tal is longitudinally divided 

 by a straight ridge ; angle of the pra^operculum somewhat 

 produced backwards ; operculum small ; sub- and intcroper- 

 culum narrow. 



Scales very regularly arranged ; lateral line straight, run- 

 ning along the middle of the tail. 



The vent is situated far backwards, its distance from the 

 caudal being less than the length of the head. 



The dorsal iiu is low, but the anterior rays are somewhat 



