178 Dr. E. L. Trouessart — Synoptical Revision 



line, passing beyond the mandibles and the hypostome, their 

 extremities being directed downwards (and not inwards, as in 

 Rhombognathus). No additional joint in the tarsus ; legs of 

 six joints. 



By the arrangement of the parts of the mouth, this genus 

 approaches Leptognathus rather than Rhombognathus. It 

 may be regarded as a Leptognathus with a much shortened 

 rostrum. A single known species. 



1. Simognathus sculptus. 



Pachygnathus sculptus, Brady (3), p. 306, pi. 42. figs. 1-6. 

 Simognathus sculptus, Trouessart (0), p. 1179, & (10), p. 162. 



Char. Legs nodose, with angular joints, especially the 

 penultimate joint of the anterior pair, which is armed with a 

 strong spine at its posterior and inferior angles. Claws not 

 pectinated; those of the anterior feet stronger and less re- 

 curved than those of the other feet. All the plates of the 

 cuirass (except the sternal and ventral plates) strongly pitted, 

 as also the hypostome and the first three joints of the legs. 

 Total length 0'42 millim. 



Hab. This fine species appears to occur only upon rocky 

 bottoms, at depths varying from 10 to 50 metres. Shores of 

 France : Kochers de Basse Kikerie (near Le Croisic), 

 dredging by means of swabs (Chevreux), a single individual. 

 English coast : Durham and N. Yorkshire, Robin Hood's 

 Bay (Brady), at 35 fathoms. 



Genus COLOBOCERAS, gen. nov. 



Char. Rostrum cylindro-conical, with lateral palpi parallel 

 to the sides of the rostrum, formed of three joints — the first 

 short, the second three times as long ; the third rather short, 

 conical, terminated by a small point. Mandibles styliform, 

 terminating in two long setas. Legs of five joints. 



This new genus approaches Halacarus more than any other 

 o-enus, and may be regarded as forming the passage between 

 Rhombognathus and Halacarus. It differs essentially from 

 the latter by its palpi, which have only three joints, the third 

 and fourth appearing to be soldered into one. Only one 

 species known. 



1. Coloboceras longiusculus, sp. n. 



Char. Body elongate, of a garnet-red colour, nearly black ; 

 the legs of a lighter red, much shorter than the body, slightly 



