Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 223 



The antennulae have the basal article greatly enlarged reaching to 

 the base of the eyestalk and the frontal margin; the free joints are 

 much reduced and fold transversely within the fossett. 



The antennae have the first free joint nearly as wide as long, with 

 its distal margin furnished with numerous long, stiff setae; the next 

 joint long, cylindrical; the flagellum half as long as the eyestalk. 



The great cheliped of the male has the meral and carpal joints 

 projecting beyond the body for a distance equal to the greatest width 

 of the carapace ; while the propodus, folded across in front of the 

 animal, extends the tip of its fingers beyond the opposite side of the 

 body ; the height of the palm is nearly equal to its length in the median 

 line ; the outer and upper surfaces are smooth, moderately rounded ; 

 the proximal part of the inner face of the palm is excavate and fits 

 upon the carpus, the upper proximal border of the palm folding above 

 the carpus when reflexed, its margin granulate. The oblique granulate 

 ridge on the inner surface of the palm is bent almost at right angles 

 and is continuous to the upper margin. The lower finger is one and 

 one-fifth times as long as the palm and the upper is one and two-fifths 

 times as long as the palm, its tip distinctly down-curved. There is a 

 very wide gape between them throughout their entire length; the 

 cutting edge is finely dentate, one rudimentary tooth on each finger. 



The small cheliped is one and two-thirds times as long as its adja- 

 cent ambulatory, has the palm small, the fingers weak, subequal, 

 widely gaping. The chelipeds of the female are subequal, both very 

 weak and similar to the small male cheliped. 



The ambulatories are slender, decreasing in length in the following 

 order: 3, 2, 1 and 4; each has the meral joint somewhat widened and 

 roughened on the upper surface, with series of transverse granulae; 

 the dactyli are slender, falcate, margined laterally with fine setae ; a 

 longitudinal groove on the outer lateral face. 



Synonymy. — Gelasimus coloradoensis Rathbun, Proc. U. S. Nat. 

 Mus., vol. 16, p. 246, 1893. 



Uca coloradoensis Holmes, Occas. Papers Calif. Acad. Sci., vol. 7, p. 

 76; 1900; Rathbun, Bull. 97, U. S. Nat. Mus., p. 410, pi. 147, 

 1918. 



