280 University of California Publications in Zoology [Vol. 23 



Uca musica Rathbun 



Plate 50 



Uca musica Eathbun, Proe. U. S. Nat. Mus., 47, 127, text fig. 5, pi. 10, 

 1914; Bull. U. S. Nat. Mus., 97, 417, text fig. 171, pi. 154, 1918. 



Fig. 165. Uoa musica, <$, X 3%; a, lower view of large (left) chela, showing 

 stridulating ridge; b, anterior (lower) view of portion of first left ambulatory 

 leg, showing granules which play against stridulating ridge (after Eathbun). 



Characters. — Carapace smooth, strongly convex, subcylindrical ; anterolateral 

 angles subrectangular ; front less than one-fourth the width of the carapace. 

 Hand of large cheliped granulated; with a very prominent ridge across inner 

 surface of palm, bent at an obtuse and rounded angle, and armed for nearly 

 its whole length with a row of large tubercles. Near the proximal lower corner 

 of the inner surface is a longitudinally oblique stridulating ridge, extending from 

 the articulation with the carpus to the lower marginal line of the palm almost 

 below the angle of the transverse ridge. The stridulating ridge is made up 

 of closely placed parallel lines, oblique to the axis of the ridge and subparallel 

 to the lower margin of the palm. When the cheliped is flexed the ridge plays 

 against a line of granules on the lower or anterior surface of the first ambulatory 

 leg; this line extends nearly the whole length of the carpal segment and part way 

 along the merus. Abdomen of male with third to sixth segments fused. 



Dimensions. — Type, male: length of carapace 8 mm., width 12.9 mm. 



Color. — Prevailing tint of carapace and limbs (in spirit) blue, of varying 

 intensity, shading in parts into greenish and on the fingers of the chelipeds into 

 white (Lockington, from Eathbun). 



Type Locality. — Pichilinque Bay, Gulf of California. 



Distribution. — Vancouver Island, British Columbia, to Guaymas, Mexico (Eath- 

 bun). 



