MUSEUM OF COMPARATIVE ZOOLOGY. 119 



Herbs! He refers to Seba, |>1 xxii, fig. 6. Seba's fig. 22 of pi. xix is a 

 better representation of the species under consideration. 



Littoral on the reef at Eastern Dry Rocks. 

 Reef at Cruz del Padre, Cuba. 

 Key West, in 2 to 5 fathoms 



Family TYCHIDAE. 



Subfamily TYCHINAE. 



Tyche einarginata White. 

 Tyche einarginata White, Annals and Magazine of Natural History, First 



Series, Vol XX. p. 206. 

 Platyrinchwi Iritnbercuhitus Desbonxe et Schramm, Crust, de la Guadeloupe 



p. :i ; pi. iii, ligs. T and 8. 



The curious genus Tyche is so little known that a short description of 

 the crab under consideration may not be out of place here. The carapax 

 is flattened and partly concave above, and has laniinilbnn expansions in 

 front and behind. The frontal region is very broad, the transorbital width 

 nearly equalling that across the branchial regions. The hepatic region is 

 concave. Rostrum rather long, forked from the base ; horns widely diver- 

 pent. Prajorbital spines very long, and somewhat divergent, thus, with 

 the rostrum, giving the entire front a tour-horned form. External antenna' 

 concealed beneath the rostrum. Eyes long but reaching scarcely beyond 

 the edge of the expanded orbit. d margin, which is entire, without nop h or 



oolll. 



The external maxillipeds are very remarkable in form, the exognath 

 having a hook-shaped process at the base, which nveTaps the base of the 

 ischiuin-joinl of the endognath. The meros-joint of the endognath has ;l . 

 posterior lobe which projects fir into the anterior extremity of the ischium. 



This crab was found by the expedition at Key West in 2 to ."> fathoms, 

 and al the Tortugas in 7 fathoms. 



Family EURYPODIIDAE. 



Among tin 1 general characters of this family, the existence of a distinct 

 orbital arch over the base of the eye, and of a postocular spine, seem to be 

 the most important. 



Subfamily COLLODIjSTAE. 



'I his name is proposed for a group nfgi nera of Eurypodiidae character- 

 ized by the extreme shortness of the rostrum, which group is. as far as 

 known, peculiar to the tropical parts of the American sea-, and occurs on 

 both sides of the continent. 



