THE BRACHYURA AND MACRURA OF PORTO RICO. 
109 
Dimensions of female: Length of body from tip of rostrum to tip of telson, 25 mm.; length of 
carapace, 9.3 mm.; length of carapace to the median spine at base of rostrum, (3.3 nun.; height of 
carapace, 7 mm.; width of carapace, 5.5 mm.; length of second pair of feet, 18 mm. 
Type locality, Ponce, I female (Cat. No. 23784). 
This species approaches A. inlrinsecus Bate, but differs from it and from all other species of the 
genus in having a median dorsal spine at base of rostrum. A specimen of .1. armatus, an ovigerous 
female, larger than the type, was taken in Kingston Harbor, Jamaica, bv Dr. J. E. Duerden. The 
rostro-orbital spine is shorter than in the type, not reaching beyond middle of cornea. The rostrum 
and antennular scales are equally advanced. Antennal flagellum is 1.5 times the length of body. 
The large cheliped is missing, as in the type. The small cheliped has a merus about three times 
as long as broad, inner margins spinulous, outer margin terminating in a small spine. Carpus short, 
subspherical, its distal margin on the outer side with a prominent tooth. Palm nearly as long as merus, 
subcylindrieal, narrowing a little distally, somewhat angular, its upper surface with two marginal lines; 
surface clothed with long hairs which arise from scabrous granules or spinules; palm with a sharp spine 
on outer and another on inner side of its distal margin. Fingers longer than palm, cylindrical, of equal 
size, bent downward, tips strongly curved, sharp, crossing each other; prehensile margins very finely 
denticulate and closing tightly together. Length of carapace, 13.6 mm. 
\ 
Genus SYNALPHEUS Bate, Coutiere. 
Synalpheus Bate, Challenger Rept., Zool., xxiv, 572, 1888: Coutiere, Ann. Sci. Nat. (8), Zool., ix, 334, 1899. 
Carapace smooth. Front tridentate or trispinous, the orbital arches being formed by the well- 
developed extra-corneal spines, completed frequently by a vertical prolongation from base of rostrum. 
A pterygostomian spine present. Antennules with basal article the longest; basal spine wide, equal to 
sum of two first articles. Distal article of third maxillipeds elongate, armed with strong spinules at 
tip. Thoracic feet without epipods. First pair very asymmetrical. Large cheliped with carpus very 
short; propodus ovoid, smooth, entire; movable finger very short. Small cheliped with the carpus 
frequently elongate and cylindrical, palm entire and smooth, lingers exactly joining. In Porto Rican 
specimens the carpus of the second pair has the first joint twice or more than twice the fifth, and the 
second, third, and fourth joints very small and subequal. Third to fifth pairs with propodi feebly 
spinulous; dactyli always bifid, sometimes triunguieulate. 
Key to the Porto Rican species and subspecies of the genus Synalpheus. 
A. Antennular scale overreaching first antennular segment. 
B. Dactylus of larger cheliped less than half the length of palm minus 
B'. Dactylus of larger cheliped at least half as long as palm neptuniis 
A'. Antennular scale not reaching beyond lirst antennular segment. 
B. Basal antennal spine elongate, surpassing the spine of scale 1 henimanus parfaiti 
B'. Basal antennal spine shorter than the spine of scale, but still surpassing t.ie first antennular segment. 
lievimanus longicarpus 
Synalpheus minus (Say). 
Alplieus minus Say, Jour. Acad. Nat. Sci. Phila. , I, 245, 1818. 
Alpheub irielentulatus Dana, Crust. U. S. Expl. Exped., i, 552, 1852; pi. xxxv, f. 4, 1855. 
Alplieus saulcyi Guerin, in La Sagra's Hist. Cuba, 2d part, vol. vn, p. xvm, pi. ii, f. 8, 1857. 
Alplieus prxcox Herrick, Johns Hopkins Univ. Circ., vn, No. 63, p. 37, 1888. 
Alplieus saulcyi var. brevicdrpus Herrick, Mem. Nat. Acad. Sci., v, 381, pi. iv (colored), 1891. 
Synalpheus minus Coutiere, Bull. Soc. Entom. France, 1898, No. 8, 190, iig. 4. 
Rostral and orbital spines present, the rostral reaching to middle of first, antennular segment and 
a little longer than orbital. Antennular scale reaching to about middle of second segment. Antennal 
scale as long as antennular peduncle, shorter than antennal peduncle. Basal spine reaching to end of 
antennular segment. Dactylus of large cheliped less than half the length of palm. Carpus of small 
first cheliped very short, hemispherical. 
Length of Porto Rican specimen, 11.5 mm. 
Taken by the Porto Rican expedition at Mayaguez Harbor, 4 to 6 fathoms, station 6065; Mayaguez, 
on coral reef; Puerto Real; Playa de Ponce; Arroyo; off Vieques, 15 to 16 fathoms, stations 6091, 6092; 
