THE BRACHYURA AND MACRURA OE PORTO RICO. 
119 
or beyond the end of antennular peduncle. Third, fourth, and fifth pairs diminishing very slightly in 
the order named, the third pair being a little longer or shorter than second. Sixth abdominal segment 
nearly twice as long as fifth. 
Length, 57 mm.; length of carapace and rostrum, 24 mm.; length of rostrum, 14.2 mm. 
Varieties occur with much shorter rostrum, having the appearance of typical specimens from 
which a portion of the rostrum has been broken off. In the Porto Rican specimens from El Yunque 
the rostrum extends to the end of the first antennular segment or to the middle of second segment. 
This form is equivalent to Xiphocaris brtvirostris Pocoek. In the individuals from Rio Grande do 
Arecibo the rostrum extends to the end of the second antennular segment or to the middle of the 
third. This form is Xiphocaris gladiator Pocock. The specimens from the other localities are typical. 
It may be noted also that while the different forms are represented by specimens of equal length, the 
brevirostris form is thicker than the gladiator or than the typical elongata. 
Porto Rican localities: Rio Caguitas, Caguas, 75+ specimens; Rio Grande, near mouth of Rio 
Caguitas, 5 specimens; Rio Bayamon, 15 specimens; Rio Grande de Arecibo, at the falls (A. B. Baker, 
coll.), 2 specimens (rostrum of the form of Xiphocaris gladiator Pocock); El Yunque, 31 specimens; 
Rio Arecibo (Gundlach). 
Known only from the fresh waters of the Antilles: Cuba (Guerin, von Martens); Haiti (Saussure) ; 
Santo Domingo (Shai-p); Dominica (Pocock); Port Castries, St. Lucia, in small brook (Albatross). 
ATYA Leach. 
Atys Leach, Trans. Linn. Soc. London, xi, 345, 1815. (Preoccupied.) 
Atya Leach, Zool. Misc., hi, 29, 1817. 
Atyoida Randall, Jour. Acad. Nat. Sci. Phila., viit, 140, 1839; A. Milne Edwards, Ann. Soc. Entom. Prance (4), iv 151, 1864. 
Rostrum short, flat, and broad at the base, horizontal or depressed. Pereiopoda without exopo- 
dites; first two pairs short, with carpal joints distally deeply excavate, infero-distal angle articulating 
with outer margin of propodus; propodus and daetylus subequal in size and fringed with long hair; 
no distinct palm; third pair of feet large and long; third and fourth pairs diminishing successively in 
size. Abdomen with sixth segment not elongate; telson broad, rounded at the end. 
Atya scabra Leach. 
Atys scaber Leach, Trans. Linn. Soc. London, xi, 345, 1815. 
Atya scabra Leach, Zool. Misc., in, p. 29, pi. 131, 1817: Ortmann, Proc. Acad. Nat. Sci. Phila. 1894, 409, and synonymy. 
Rostrum reaching nearly or quite to end of first antennular segment and with a median and a 
lateral carina; either triangular or with lateral carina terminating in a tooth above eye. Carapace 
deeply punctate; anterior margin with an external orbital and a branchiostegal tooth or spine. First 
and second pairs of feet subequal, terminal hairs reaching to or beyond antennal scale. Third, fourth, 
and fifth pairs of feet covered with short spines. In typical specimens the third pair of feet are very 
heavy, the merus being much swollen between middle and distal end; carpus and propodus subequal 
in length; daetylus very short. Fourth and fifth pairs much shorter and more slender, subequal in 
thickness. 
This species is extremely variable in the form of the rostrum and more noticeably in the shape 
of the last three pairs of thoracic feet, which may all be slender and nearly equal in length; and their 
spines very feeble and appressed. These differences are independent of sex or size, and probably 
represent different stages in the growth of the individual. 
Length of Porto Rican specimen, a male with feet of third pair stout, 66 mm.; length of carapace 
and rostrum, 26.8 mm.; of rostrum, 4 mm. Length of male specimen with feet of third pair slender, 
80.5 mm.; length of carapace and rostrum, 29 mm; of rostrum, 6.5 mm. 
Porto Rican localities: San Juan market; MayagUez, fresh water; Falls of Rio Grande de Aibonito; 
Falls of Rio Grande de Arecibo (A. B. Baker, coll.); El Yunque; a tributary of the River Anasco, and 
San Juan market (Gundlach). 
Common to the fresh waters of Mexico, Nicaragua, Costa Rica, West Indies, West Africa and 
adjacent islands; Orinoco; Venezuela (Lyon and Robinson coll. ). 
Common name, Guabara (Gundlach). 
