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PACIFIC SCIENCE, Vol. XIII, April, 1959 
Coutiere 1899: fig. 293). Yet the illustrations 
showed slight differences in the sculpturing 
(contrast Bate, fig. 2k to Coutiere, he. cit). 
In contrast, the specimens reported from Ha- 
waii (Banner, 1953: 134) did not show the 
sculpturing, nor did those reported from Arno 
Fig. 11 . Alpheus crassimanus Heller. Variation in form 
of small chelae, a, 22 mm. ovigerous female; b, 22 mm. 
male; c, 27 mm. male, lateral aspect; d, same, medial 
aspect; c, 24.6 mm. male. Specimens shown in a-diiom 
Yap, e, from Hawaii; all drawn to same scale. 
and Onotoa (Banner, 1957: 204; 1958: 168). 
The three specimens from Yap indicate a 
possible reason for this difference. One of the 
specimens is an ovigerous 22 mm. female, 
which shows a slight trace of sculpturing in a 
shallow, ill-defined depression located longi- 
tudinally on the upper surface of the palm. 
The male of the same size has the character- 
istic dactylus of the adult male, yet the palm, 
like that of the female, bears only a slight 
longitudinal depression. However, in the 27 
mm. male the palm is strongly sculptured. It 
is very roughly triangular in cross section, 
with the upper medial and lateral faces bear- 
ing extensive depressions that are quite well 
deliminated (although not as definite as the 
corresponding depressions on the large chela) ; 
these are connected across the superior margin 
by a rounded, saddlelike transverse groove. 
On the inferolateral margin there is a strong 
shoulder; the inferior surface of the chela is 
flattened and demarked by abrupt but rounded 
margins; the inferolateral shoulder does not 
continue on the inner face. 
Specimens from Hawaii were re-examined, 
and while the smaller males show almost no 
trace of the sculpturing, the largest male 
available (24.6 mm. long, collected in the mud 
flats at Heeia, Kaneohe Bay, Oahu in about 
plus 1 to 2 ft. tide zone) shows sculpturing 
similar to that of the 22 mm. Yap specimen. 
Inasmuch as specimens less than 20 mm. 
long are often ovigerous, and inasmuch as 
specimens up to 44 mm. long have been re- 
ported (de Man, 1902: 880), it appears that 
the younger, but mature, males bear the sub- 
spatulate dactylus but may be entirely lacking 
in the sculpturing of the palm, while larger 
males develop the sculpturing. It is likely that 
the point of transition between the two forms 
may be around the body length of 25 mm., 
although this size may vary in different geo- 
graphic areas. For example, none from Ha- 
waii appear to reach the necessary size, while 
the specimen reported by de Man from 
Makassar {loc. cit.) evidently had the sculptur- 
ing at a body length of 25 mm. 
