516 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



Uca macrodactyla Crane, Zoologica, vol. 26, no. 19, p. 178, 1941 ; part: 

 the Galapagos specimen. 

 Type locality. — Indefatigable Island. 

 Type.—\]?>NM No. 22319. 



Range. — Known only from the Galapagos Islands, Indefatigable, 

 James, and Seymour. 



Diagnosis. — Superior margin of palm with a granular ridge. Orbital 

 margins moderately oblique. Front about one-third width of carapace. 

 Size large. 



Material examined (173 specimens from 6 stations). — 

 8-32. E. of Post Office Bay, Charles Island, shore, Jan. 3, 1932, 16 

 males, 3 females, fragment. 

 39-33. Flamingo Lagoon, Charles Island, shore, Jan. 29, 1933, 39 



males, 12 females, (including photographed pair). 

 49-33. Academy Bay, Indefatigable Island, shore, Feb. 3, 1933, 29 

 m.ales, 19 females. 

 82a-33. Conway Bay, Indefatigable Island, shore, Feb. 17, 1933, 2 

 males. 

 88-33. South Seymour Island, shore, Feb. 19, 1933, 38 males, 15 

 females. 

 314-35. Academy Bay, Indefatigable Island, shore, Dec. 7, 1934, 5 

 males, 2 females. 

 Measurements. — Largest specimen, male: length 14.6 mm, width 

 22.1 mm, cheliped 60 mm, chela 38.6 mm, dactyl 28 mm; female: length 

 13.5 mm, width 19.6 mm. 



Habitat. — In mud flats of brackish lagoons. 

 Depth. — Shore. 



Remarks. — Brackish water and claylike soil are sought by the fiddler 

 crabs in general. The Galapagos species, U. galapagensis Rathbun, thrives 

 equally well in a pinkish muck at Charles Island or a red-orange gumbo 

 at South Seymour Island. The Academy Bay specimens, living in gray 

 mud, attain the greatest size. 



The Eden Island specimen figured by Boone (1927, fig. 97, upper 

 figure) has been examined through the kindness of Miss Jocelyn Crane 

 of the New York Zoological Society and found to be in close agreement 

 with the large series of galapagensis taken by Velero III collectors at 

 Academy Bay, on the opposite side of Indefatigable Island. In view of 

 this fact and the fact that Miss Crane considers the specimen to be atypical 

 as U. macrodactyla, the specimen is here referred once more to the estab- 

 lished Galapagos species until others unquestionably of the latter species 

 put in an appearance. 



