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, 
116; 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 
sur-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- 
9my, and particularly the arrangement of the branchie, and 
the Structure of the lateral apodemes can be observed. It 
55 obvious that this genus most strongly represents the 
Brachy oura in the section to which it belongs. The — 
Pax, usually of moderate or small size in the Anomoura, is 
here developed to a degree unequalled in any of the higher 
. capods, not excepting even Cryptopodia and Œthra. It 
75 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. 
