Genera of the Dromiidjic. 301 



Tlie following- key sets forth, in a more or less empirical 

 waj, the principal characters of tiie genera of Droraiidse* : — 



I. No vestige of tlie sixth abdominal limb. 



Last joint in legs of hinder two pairs has 

 the shape of a half-moon, fastened by its 

 outer side to the end of the leg. [No epi- 

 podite on the cheliped. Sternal grooves 

 end apart on segment of second walking- 

 leg. Carapace incompletely and more or 

 less indistinctly divided into reo;ions.] . . Ilypocoucha, Guer., 1854. 



II. A vestige of the sixth abdominal limb. 



Last joint in legs of hinder two pairs has 

 the shape of a hook, fastened at the blunt 

 end to the leg. 



A. Sternal grooves not reaching level of 



genital opening. Front triangular, 

 notched in the middle. [Carapace sub- 

 globose, without regional grooves in the 

 fore part. Epipodites ':] Sphccrodromia, Ale, 1899. 



B. Sternal grooves reaching level of genital 



opening. Front usually with a middle 



tooth and one on each side. 



i. Fourth pair of legs shorter than third, 



but stout and ending in a very large 



hooked joint. Carapace flat. [Fifth 



leg slender. Epipodite on cheliped. 



Sternal grooves end apart.] Conchoecetes, Stinips., 



ii. Fourth pair of legs not as in Conchm- [1859. 



cetes. Carapace more or less swollen. 



a. Front deeply cleft into two bitid 



lobes. [No epipodite on cheliped. 

 Sternal grooves end apart on cheli- 

 ped-segiuent.J. Laslodromia^ Ale, 1901. 



b. Front not as in Lmiudromia. 



1. Epipodites on the chelipeds. 

 u. Sternal grooves end together. 



Carapace longer than broad. 



Almost without regions. 



Usually a thorn on the outer 



side of the last joint of the 



fifth leg Dromidiopsis, Borradaile, 



/3. Sternal grooves end apart. Cara- [1900. 



pace usually broader than long. 



Regions more or less clearly- 

 marked. No thorn on the 



outer side of the last joint of 



the fifth leg. 



(1) No ridges on the legs. Cara- 



pace not granular Droniia, Fabr., 1798. 



(2) llidges on the legs, some of 



* For lack of information I am unable to include Fseudodrotnia, Stimps 

 1859 (Proc. Ac. Philad. 1858, p. 220), or P/«^y<^ro/«m, Fulton and Grant' 

 1902 (Proc. Koy. Soc. Victoria, 1902, p. 55). The first of these genera 

 .«oen)s to be closely allied to Droinidia, and the second should perhaps 

 be placed somewhere in the neighbourhood of Cryptodrvmioimn, 



