464 PROCEEDINGS OF THE NATIONAL MUSEUM vol. si 



it, it may have a small tubercular or nodular projection intervening 

 between the anterior and posterior spine. 



The hands, however, appear to resemble more closely those of 

 A. Uruguay ana in most particulars : Low or no crest, anterior sharp 

 spine on inner margin, and no lobe on outer margin of movable finger. 

 The palm of A. sanlorenzo is relatively shorter than that of A. uru- 

 guayana, and the fingers lack the lobular teeth present in the last- 

 named species. 



AEGLA PLATEN SIS, new species 

 FiGUBES 45, 46; Plate 25, C 

 Aegla laevis R. von Ihering, Atlas da fauna do Brasil, pi. 4, fig. 17," 1917. 



Description. — A large species, attaining a length of carapace and 

 rostrum together of about 39 mm. 



Carapace, though gently convex, more or less flattened, front very 

 wide. Rostrum an elongate ridge-roofed, narrowly triangular spine, 

 exceeding eyestalks by about twice the length of the cornea ; rostral 

 carina somewhat blunt, only fairly sharp ridged, furnished with 

 three to five rows of cornified, sometimes almost microscopic punctae, 

 except very close to anterior extremity of rostrum, where there is an 

 irregular, short, single row of larger corneous scales ; carina runs back 

 as far as the anterior margins of the protogastric lobes, neither proto- 

 gastric lobes nor epigastric prominences at all well marked. Anterior 

 margins of protogastric lobes broadly obtuse angled, not at all tuber- 

 culiform at apex of angle. Areola widens noticeably behind. 



Orbital sinus wide, but only a little longer and a little wider ap- 

 pearing than extraorbital sinus, orbital spine well developed. An- 

 terolateral spines large and conspicuous, reaching nearly or about 

 to middle of cornea. Anterolateral angle of first hepatic lobe is 

 produced into a prominent, sharply acute spine; second and third 

 hepatic lobes may be indicated, but are not at all well marked; if 

 spinulated, spinules no larger than spinules found elsewhere on lateral 

 margin of anterior portion of carapace; occasional specimens may 

 have a small notch marking the second hepatic lobe on one or the 

 other side of the carapace, perhaps never on both sides. 



Hands large, broadly ovate, much flattened as compared with most 

 species of Aegla. Movable finger more or less cylindrical, rather 

 slender in well-developed specimens, and arched, making a consider- 

 able gape between the fixed and movable fingers ; movable finger with 



" This figure of Rudolfo von liiering is original and is undoubtedly based on one of a 

 lot of specimens collected by his father Hermann von Ihering, in the State of Rio Grande 

 do Sul (collector's No. 619). The Rio Grande do Sul record given under "Distribution" 

 of A. platensis below is also based on a specimen from that lot of material, presented to 

 the U. S. National Museum by Dr. H. von Ihering in 1915. A comparison of this specimen 

 and the figure convinces me that A. platensis is the species represented. 



