280 University of California Publications in Zoology [Vou 28 
Uca musica Rathbun 
Plate 50 
Uca musica Rathbun, Proc. U. S. Nat. Mus., 47, 127, text fig. 5, pl. 10, 
1914; Bull. U. S. Nat. Mus., 97, 417, text fig. 171, pl. 154, 1918. 
a b 
Fig. 165. Uca musica, 3, 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 Rathbun). 
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 Rathbun). 
Type Locality—Pichilinque Bay, Gulf of California. 
Distribution—V ancouver Island, British Columbia, to Guaymas, Mexico (Rath- 
bun). 
