of the Pacific Shores of North America. 475 



when drawn out they reach the fourth joint of the preceding 

 pair. 



The abdomen is flattened, and without spines or tuber- 

 cles. In the female it is symmetrical externally, although 

 provided with ovigerous legs on the left side only. The 

 basal (second^ article is undivided, arched, broad and con- 

 cave. The three following each consist of a convex, quad- 

 rilateral, tergal piece, transversely ridged across the middle, 

 and the lateral or epimeral pieces, which are placed obliquely, 

 and are wider than long, with their margins raised, and 

 their surface depressed. The sixth article is unprovided 

 with epimeral pieces ; it is longer than the preceding ones, 

 of a trapezoidal shape, its sides joining the posterior edges 

 of the epimera of the article next preceding ; its broader 

 terminal side is deeply sinuated for the reception of the 

 seventh article. This latter is very small, triangular, and 

 fits between the basal joints of the anterior pair of feet 

 when the abdomen is in place. 



The color was reddish beneath ; above indistinct. The 

 dimensions of the specimen above described are : length, 

 1.16 ; breadth, 1.85 inch. Proportion, 1:1.60. The dimen- 

 sions of Brandt's specimen were : length, 1.33 ; breadth, 

 1.91 inch. Proportion, 1:1.43. 



The Smithsonian specimen was found by Mr. Taylor on 

 surf-washed rocks near low-water mark, on the beach of 

 Monterey. It is desirable that other specimens should be 

 secured and well preserved in spirits, in order that the anat- 

 omy, and particularly the arrangement of the branchiae, and 

 the structure of the lateral apodemes can be observed. It 

 is obvious that this genus most strongly represents the 

 Brachyoura in the section to which it belongs. The cara- 

 pax, usually of moderate or small size in the Anomoura, is 

 here developed to a degree unequalled in any of the higher 

 Decapods, not excepting even Cryptopodia and CEthra. It 

 is indeed the only instance in which the cephalo-thorax 

 entirely conceals the feet ; in all other genera the anterior 

 pair at least being seen from above. 



