97 



with a line of four or five aculei. Length of a male from tip of 

 rostrum to extremity of abdomen, l41 n ™. Length of carapax from 

 orbit to middle of posterior border, 60.8; height of carapax, 29.5. 

 Length of rostrum, 16.4. Third thoracic legs, entire length, about 80 ; 

 merus, 42; carpus, 20; propodus, 7; dactylus, 10. 



Young, less than 30 mm - in length, do not differ from the large speci- 

 mens, except in having the third pair of thoracic legs a very little 

 less robust, and the spines of the carapax, etc., slightly less developed. 



Eresh water streams, Polvon, and the "Rio Fulva, two and a half 

 miles northwest of Eealejo;" both localities in the Occidental De- 

 partment of Nicaragua. 



Leander gracilis, sp. nov. Female. Rostrum very long, strongly 

 curved upward in the middle of its course, and the terminal portion 

 very slender ; the upper edge armed with eight or nine teeth, of which 

 six or seven are on the basal half and the others near the tip, and 

 the under edge with nine or ten small teeth, which decrease in size 

 anteriorly and become very minute near the tip. Outer flagellum of 

 the antennula slender and much longer than the entire body ; inner 

 flagellum only slightly shorter. Flagellum of the antenna slender and 

 fully twice as long as the rest of the animal. First thoracic legs 

 reaching nearly or quite to the tips of the antennal scales, very 

 slender, and naked, except a few hairs on the fingers. Legs of the 

 second pair reaching to the tip of the rostrum, very slender and 

 nearly naked ; hand, about three-fifths as long as the carpus, cylin- 

 drical, very slender and delicate, the fingers nearly as long as the 

 palmary portion. Abdomen rounded and smooth above, the lateral 

 portions of the first three segments with shallow vertical sulci, sixth 

 segment compressed laterally and about twice as long as the fifth. 

 Lamellse of the sixth segment very narrow, the extremities ovate, 

 the inner ones extending slightly beyond the tip of the abdomen, 

 the outer ones much longer. Terminal segment narrow and tapering 

 regularly to a very slender and acute point. A specimen with eggs 

 beneath the abdomen gives the following measurements : Length of 

 body from tip of rostrum to extremity of abdomen, 43.2 mm - Length 

 of carapax from orbit to middle of posterior margin, 7.5; length of 

 rostrum from tip to base of eyes, 11.7; length of basal scale 

 of antenna, 7.9; length of first thoracic legs, 12.6; length of second 

 thoracic legs, 17.0; merus, 3.5; carpus, 5.6; hand, 3.3; dactylus, 1.5. 



"Estero at Realejo," west coast of Nicaragua. 



Palcemon Jamaicensis Olivier, Edwards, Hist. nat. des Crust., tome 

 ii, p. 398 ; Martens, Wiegm. Archiv xxxv, 1869, p. 22. A large 

 number of specimens from Polvon, Occidental Department of Nic- 

 aragua, agree with the descriptions of this species and with a 

 Brazilian specimen. In several of the very large specimens the legs 

 p. a. s. 13 



