ZooL— Vol. III.] HOLMES— WEST AMERICAN CRUSTACEA. 309 



extending towards the base of the dactyl; the prominent lower margin of the 

 carpal groove extends backwards from the angle where these ridges meet 

 in the same direction as the upper ridge; the meeting point of the 3 ridges 

 forms the apex of a large, high, three-sided pyramid. A line of small 

 granules extending backwards from the inner margin of the pollex and 

 dividing into 2 branches which run on either side of a groove lying behind 

 the base of the dactyl; pollex gently curved, the inner margin granulated on 

 the basal portion and armed with a few teeth on the distal half; tip trun- 

 cated; dactyl curving from near the middle, overreaching the pollex, the 

 inner margin granulated and furnished with a few small teeth. Ambulatory 

 legs slender and hairy, the meral joints narrow and marked with scattered, 

 sparingly setose striae; dactyls slender, smooth, sulcated, and about as long 

 as the propodi. Abdomen in the male broad, che third, fourth, and fifth 

 segments successively increasing in length and decreasing in width; sixth 

 segment a little narrower than the fourth but about as long. There is a 

 dense tuft of fine hair on the posterior side of the coxa of the second, and on 

 the anterior side of the coxa of the third pair of ambulatory legs. 

 Color of the carapace in alcohol dark olivaceous. 



Male. Female. 



Length of carapace 20.5 mm. 18 mm. 



Posterior margin of carapace 15 mm. 15.5 mm. 



Breadth of carapace 29 mm. 25 mm. 



Length of large hand 55 mm.; merus 18 mm.; carpus 15 mm. 



Todos Santos, Lower California, in a lagoon (Stimpson) ; 

 Magdalena Bay (Lockington) ; San Jose del Cabo, Lower 

 California, from fresh water. 



Described from numerous specimens from the last 

 locality, collected by Eisen and Vaslit. 



Uca brevifrons has been united with U. vocator (Herbst) 

 by Kingsley and more recently by Ortmann; but it differs 

 from Herbst's description of vocator and from all the other 

 species which Kingsley and Ortmann regard as synonyms 

 of that form. From -pugnax (Smith), brevifrons differs in 

 its broader and less projecting front, in the much more 

 convex lower border of the upper orbital margin, in having 

 the inner surface of the carpus of the larger cheliped 

 devoid of an oblique tuberculated ridge, in the more 

 slender meral joints of the ambulatory legs, and in its 

 larger size. 



From U. crenulata (Lockington) which has also been 

 erroneously united with vocator, it differs in its relatively 

 narrower carapace with a shorter posterior margin, the 



