DATNIA, &C. 165 



circumstance not common among Cuvier's Percoid 

 Fishes. The greater numbers are found in the 

 Indian Seas. 



Datnia differs from the true Therapon in 

 the form of the body being much broader, or the 

 outline raised ; the jaws pointed ; no teeth on the 

 palate, and in the spines of the first dorsal fin 

 being extremely strong. Two species only are 

 referred to this form by Cuvier found in the 

 rivers of India. The Caius datnia of Hamilton 

 Buchanan, from the Ganges, will serve as an 

 example. 



Pelates has the dorsal fin of a more equal 

 size ; the opercle with two weak spines, scarcely 

 passing the membrane, and no teeth on either the 

 vomer or palatine bones. Three species, from 

 the New Holland Seas, seem all that are known, 

 characterized by comparatively small scaling, and 

 by the body being marked by longitudinal dark 

 bands. Their discovery is due to MM. Lesson 

 and Garnot. 



Helotes is distinguished principally by the 

 outer row of teeth in the jaws being divided into 

 three points. The preopercle is finely serrated, and 

 the opercle has a single weak spine. Contains a 

 species, discovered by Guoy and Gaymard in the 



