JVoies on North American Crustacea. 193 



apex with a short, deflexed spine. There are two or three tubercles on 

 the infero-lateral regions, in front of the bases of the chelipeds. Outer 

 maxillipeds with a sharp longitudinal denticulated ridge on the ischium- 

 joint ; antero-interior corner of the meros sharply projecting forwards. 

 Dactyli of the posterior three pairs of feet falciform, equal. Length of 

 the carapax in the male, 0.45 ; breadth, 0,32 inch. 



It differs from I..microrhynchus in the smoothness of its 

 carapax. 



Found at Panama, by the Rev, J. Rowell. 



Collodes,* nov. gen, 



Carapax ovato-triangularis; rostro brevi, bifido, cornibus approximatis. 

 Oculi mediocres, ad processum post-ocularem vel marginem posteriorem 

 orbitse retractiles, non sese latentes. Antennarum articulus basalis 

 angustus, paullo contortus, antrorsum bidentatus, dente uno sub altero 

 site ; pars mobilis longa, aperta. Maxillipedes extern! eis Microrhynchi 

 fere similes, mere quam ischium non angustiore, antrorsum profunda 

 inciso, angulo interno sub basin palpi valde prominente acuto. Cheli- 

 pedes mediocres. Pedes ambulatorii breves, toti prehensiles, dactylis 

 valde gracilibus, longitudine articulum peuultimum adequantibus et ad 

 eum retractilibus. Segmenta quantum ad septimum abdominis femi- 

 narum coalita. 



The orbit in this genus is incomplete ; the postero-superidr 

 limb is, however, j^resent, and is formed by the strong post- 

 ocular process, which is separated from tJie praeorbital arch by 

 a deep, open marginal fissure. The genus differs from Micro- 

 rhynchus in its feet, orbits, and rostrum ; from Achceus, in its 

 post-ocular or orbital process, and in its external maxillipeds; 

 from Ach<jeoj)sis, in its prehensile anterior ambula,tory feet, and 

 in the broader meros-joint of the external maxillipeds, with 

 sharply projecting internal angle ; from Eurypodiiis and Ore- 



* From KoWwim, tenax, in allusion to the tenacity with -which the animal 

 adheres to submarine objects with its strongly prehensile or aincoral feet. 



