74 PROCEEDINGS OF THE CALIFORNIA 



This species is mentioned by Hale Streets in his " Catalogue of Crustacea 

 from the Isthmus of Panama, collected by J. A. McNeil," but that author 

 does not state whether the specimens were from the Pacific or Atlantic shore 

 of the Isthmus. It is found at Aspinwall and along the Brazilian coast. 



TYCHIDiE. 



25. Tyche brevipostris. Nov. sp. 



Carapax an elongated rectangle with sinuate sides; rostrum short, depressed; 

 laminate; pre-orbital spine long, elevated, produced almost as far forwards 

 as the rostrum when viewed from above. A thin broad lobe behind the pre- 

 orbital spine, concealing the elongated eyes except at the tip. Fixed joint of 

 outer antennas narrow, and boldly relieved from the surrounding parts, sec- 

 ond and third joints cylindrical. Peduncles of eyes inserted level with the 

 fixed joint of antennas. Anterior portion of carapax bent downwards, poste- 

 rior portion shield-shaped, the lateral and posterior margins overhanging, the 

 latter thin. First pair of limbs shorter than second, scarcely projecting be- 

 yond the carapax. Second pair about as long as carapax, slender; succeeding 

 pairs similar. 



M. M. 



Length of carapax ... 17 



Width of ditto 11 



A single female specimen from Port Escondido, Gulf of California. 



The general aspect of this little crab is that of a dried leaf; the anterior 

 portion, deflected and somewhat pilose, does not attract the eye, while the 

 shield-shaped posterior portion is very conspicuous. From the cential tuber- 

 cle of the gastric region, which is the most elevated portion of the carapax, 

 a ridge is continued outwards on each side to tire margin of the carapax, the 

 surface of which is increased by expansions with sinuate edges. The whole 

 of this leaf-like posterior surface is inclined in the opposite direction to the 

 frontal portion. The pre-orbital spines project like a pair of horns immedi- 

 ately in front of the eye-shields, each of which is an obtuse isosceles triangle 

 with its apex directed laterally. 



As the specimen is a female it is impossible to be certain whether the small 

 chelipeds are characteristic of the species, or of the sex only. I have placed 

 this species in the genus Tyche of Bell, with which it has the following char- 

 acters in common: Eyes without orbits, hiding below the carapax, which is 

 oblong, wide in front and broad across the orbits, depressed, without post-or- 

 bital spines, and with pre-orbital spines produced to a line with the rostrum ; 

 first joint of external antennas long, unarmed. 



This form differs, however, from the generic description as given by Dana, 

 in the shortness of the rostrum, which is bent downwards, but not more so 

 than the anterior portion of the carapax. 



edbypodid^;. 



26. Oregonia gracilis. Dana. U. S. Ex. Exp., I, 106, pi. Ill, f. 2. Stimp- 



son. Crust and Echi. Pac. S. N. A., 16. 



