no. 176G. STALK-EYED CRUSTACEA OF PERI RATHBUN. 56] 



second pair very large, unequal. Rostrum short, triangular, with a 

 superior crest, dental formula §:§. A spine on anterior margin of 

 carapaee just outside orbital sinus. Inner antenna with three slender 

 flagella; outer antenna with a large scale and a very long flagellum, 

 dorso-ventrally flattened. First pair of legs slender; second pair 

 stout, spinous, the smaller one as long as the body, the larger one 

 one and a half times as long, palm compressed, wider than wrist; 

 last three pairs simple, spinulous. Telson subtriangular, with two 

 pairs of dorsal spinules, extremity rounded. 



Length of body 16 cm.; total length to end of large claw 37 cm. 



Taken at Pacasmayo from a small and rather dirty stream which flows through the 

 town, conveying to the bay the surplus water from irrigation ditches supplied from 

 the River Jequetepeque, March 12, 1907; common. 



Market of Lima, November 2, 1907. 



Market of Lima, April, 1908. The seller stated that they were brought from Chan- 

 cay. 



Market of Lima, April, 1908. Presumably from the Rimac. 



Taken in the Rimac near Villegas (below Lima), November (I, 1907. 



Arequipa, July 26, 1908. 



Mollendo, July 23, 1908. 



Distribution. — From Ecuador to Chile. 



MACROBRACHIUM JAMAICENSE (Herbst). 



Plate 51, fig. I. 



Cancer (Astcicus) jamaicensis Herbst, Natur. Krabben u. Krebse, vol. 2, 1792, 

 p. 57, pi. 27, fig. 2. 



Similar to the preceding; rostrum narrower and longer, about as 

 long as peduncles of inner antennas, teeth V:Vs an additional spine 

 on the carapace behind the marginal spine. Chelipeds of second pair 

 equal, spinous; palm slightly compressed, scarcely wider than carpus 

 and more than three times as long as wide. 



This species may attain the size <»f the preceding, but the Peruvian 

 specimens are small, body not exceeding 7 cm. 



Taken at Pacasmayo from a small and rather dirty stream which Hows through the 

 town, conveying to the bay the surplus water from irrigation ditches supplied from the 

 River Jequetepeque, March 12, 1907; common. 



Not previously known from Peru. 



Distribution. — Fresh waters of the Pacific slope of America from 

 Lower California to Peru; and of the Atlantic slope from Texas to 

 Brazil, including the Wesl Indies. 



PPALjEMON RITTERI Holmes. 



Plate 53, fig. I . 



Patemoti rifferi Holmes, Proc. Cal. Acad. Sci. (2), vol. 4, 1895, p. 579, pi. 21, 

 figs. 29-35. 



A small shrimp, allied to Macrobrachium, with smooth carapace, 



armed with two spines on each side of the anterior margin; rostrum 



Proe.N.M.vol.38— 10 36 



