Leptocotis. Ill 



more nearly cheliform than in Dorycephalus ; the best distinguishing cha- 

 racteristic is, however, the considerable elongation of the urus and its 

 appendages. But by this last characteristic Leptocotis mindanaonis, Steb- 

 BiNG, is clearly excluded from the genus, and if it be not placed in the 

 genus Streetsia^ as I think it may be, and have already suggested (above 

 p. 81), it ought to be the type for a new genus. 



The generic diagnosis given by Streets in 1877 contains only 

 a few passages which could possibly serve for characterization of his 

 new genus. They are: 



»Gnathopoda short and complexly chelate. . Caudal ap- 

 pendages long, biramous. Telson cylindrical, long». 



In 1878 he gave the following diagnosis: 



»Body long and slender. Head produced anteriorly to the superior 

 antennee in a long, slender rostrum, constricted posteriorly at its arti- 

 culation with the thorax, the constricted portion short. Superior autennse 

 short, three-jointed, curved in the male; inferior antennas five-jointed, 

 joints subequal, excepting the last which is short. Mandibular append- 

 age three-jointed. First and second pairs of thoracic legs short, chelate; 

 the third and fourth simple; the last three pairs with the basal joint 

 dilated; the last pair diminutive. The sixth abdominal segment (the fifth 

 and sixth fused) elongated. The caudal appendages long, linear. Telson 

 long, triangular at apex». 



Whether Oxycephalus tenuirostris, Claus, and Leptocotis spini- 

 fera. Streets, are identical or not is a very difficult question to settle, 

 because the authors do not record at all, or only vaguely, any details of 

 importance for specific distinction; I must therefore restrict myself to 

 giving the two species below with the characteristics which are available 

 from their descriptions. 



1. Leptocotis spinifera, Th. Streets, 1877. 

 PI. V, fig. 15—17. 



Diagn. The head^ without the rostrum, is as long as the whole 



perseon; the rostrum is slightly more than half as long as 



the rest of the head. 



The segments of the perceon increase in length backwards. The 



epimerals are long, broadly ovate, and transversely rugose. 



