THE SPECIES OF AEGLA — SCHlVnTT 467 



will always distinguish A. uruguayana from A. platensis, even in 

 very small juvenile specimens. 



In well-developed females of A. platensis the hands are flatter 

 than in the males, and also somewhat narrower; the fingers are much 

 less strong, and more slender. 



The sternal plate between the chelipeds carries a low, blunt keel, 

 which anteriorly may at times be raised a bit or project forward as 

 a low, ventrally keeled, conical tubercle; there is some suggestion of 

 similar keeling on the following sternum between the first pair of 

 ambulatory legs, which, though elevated about as much as the pre- 

 ceding keel, forms a very broad, low swelling, larger and broader 

 at the anterior end than at the posterior. 



A. uruguayana has a low median swelling on the anterior half of 

 the sternum between the chelipeds, a little peaked at the forward 

 end, but not appearing so keeled as in A. platensis; often in specimens 

 of medium size this swelling or projection takes on the form of a 

 stout, conical, corneous-tipped spine inclined obliquely forward. 



Distribution. — In addition to the type lot, I have seen various speci- 

 mens from the vicinity of Buenos Aires and from Tigi"e nearby, 

 where Dr. Martin Doello-Jurado, director of the Museo Argentino, 

 most kindly took me collecting one day; from the Prado and the 

 Arroyo Miguelete, Montevideo, and Bahia de Colonia, Uruguay ; Rio 

 Grande do Sul, Brazil; and one specimen that appears to be this 

 species from Tucuman, Argentina. 



AEGLA URUGUAYANA, new species 

 FiGUEE 47; Plate 25, D 



Description. — A species of good size, attaining a length of carapace 

 and rostrum together of 33 mm. 



Carapace moderately convex, well areolated, front wide. Rostrum 

 long, slender, and sharply acuminate, above lateral margins distinctly 

 triangular in cross section; rostrum in the type specimen exceeds 

 the eyestalks by II/2 to nearly 2 times the length of the cornea (in 

 very small specimens rostrum may be only little longer than eye- 

 stalks) ; rostral carina prominent, multiscaled, scales intermingled, 

 plainly marked backward to a little behind the level of the anterior 

 margin of the protogastric lobes. Epigastric prominences just low 

 swellings situated on the forward slope of the carapace between the 

 orbital margin and the much higher lying anterior margins of the 

 protogastric lobes; the anterior margins sharply marked by a row 

 of five or six light corneous beadlike scales. Areola of good size. 



Orbits very wide and shallow, distinctly set off from extraorbital 

 sinus by an orbital spine of good size, extraorbital sinus about three- 

 fifths as wide as the orbital sinus. 



