CLIPPERTON ISLAND DECAPODS—CHACE 613 
terminal spine on the antennal scale, the divergence of the ventral 
spine on the dactyls of the last three pereiopods, and the disposition 
of the dorsal spines on the telson. In all of the specimens examined, 
including the neotype, both pairs of dorsal spines are situated on the 
posterior half of the telson, rather than as indicated in Banner’s 
description and figure. The neotype also has the rostrum consider- 
ably narrower and the ventra] spines of the ambulatory dactyls more 
divergent than in the specimen figured by Banner. 
DistrinutTion: Known previously only from the Hawaiian Islands. 
Synalpheus nobiliit Coutiére 
Synalpheus nobilit Coutiére, 1909, p. 40, fig. 22—Schmitt, 1939, pp. 12, 24. 
Mareriat: Northeast shore, rocks south of landing place; July 21, 
1938; Sta. 9; W. L. Schmitt; 28 specimens (8 ovigerous).—Poison; 
October 20, 1956; W. Baldwin; 18 specimens (mostly juveniles, 1 
ovigerous).—EKast side, coral reef; August 9, 1958; Sta. W58-283; 
Reese, Baldwin, and Wintersteen; 1 specimen.—Kast end, coral reef; 
August 15, 1958; Sta. W58-289; Reese, Baldwin, and Wintersteen; 
13 specimens (3 ovigerous).—Northeast transect, 36 feet; August 27, 
1958; Chess and Hambly; 2 specimens (1 ovigerous).—Northeast 
transect, 78 feet; August 27, 1958; C. Limbaugh; 1 juvenile.—North- 
east side, 45 feet; August 28, 1958; Limbaugh, Chess, and Hambly; 
5 specimens.—EKast side, reef flat, margin or ridge, 0-2 feet; Septem- 
ber 14, 1958; Limbaugh and Chess; 2 specimens. 
MEASUREMENTS: Carapace lengths to base of rostrum, 2.0—7.0 
mm.; of ovigerous females, 3.7—7.0 mm. 
Remarks: Specimens that appear to be males, from the form of 
the abdominal pleura and pleopods, have a maximum carapace length 
of 5.8 mm.; the three specimens larger than this are all ovigerous. 
This species bears a resemblance to the very variable S. paraneomeris 
Coutiére, which is found throughout the Indo-Pacific region and is 
common in the Hawaiian Islands, but S. nobilii can be recognized 
readily by the prominent dorsal spine on the basal antennal segment 
(basicerite). 
DistriputTion: Known otherwise only from Ecuador and the 
Galapagos Islands. 
Synalpheus charon (Heller) 
Alpheus charon Heller, 1861, p. 27. 
Synalpheus charon Banner, 1953, p. 37, fig. 11. 
MarteriAL: Northwest end, reef; August 14, 1958; Sta. W58-288; 
Reese, Baldwin, and Wintersteen; 1 ovigerous female.—Northeast 
transect, 36 feet: August 27, 1958; Chess and Hambly; 3 specimens 
(1 ovigerous).—Northeast side, 45 feet; August 28, 1958; Limbaugh, 
Chess, and Hambly; 3 specimens.—Northeast corner, 45 feet; August 
632596—62——2 
