THE SPECIES OF AEGLA — SCHMITT 473 



The stepwise arrangement of the well-marked hepatic lobes and 

 the frequently strongly ridged carapace tend to set this species 

 apart from those that are most closely related to it. As in A. 

 Uruguayans, there is a sharp to spinous tipped tubercle on the anterior 

 sternite, but in the present species it is larger, usually sharper, and 

 more erect, forming roughly an angle of about 45° with the general 

 surface of the sternite. The ventral inner ischial borders of the 

 chelipeds are similarly armed in the two species, but in A. prado the 

 posterior tubercle is more prominent, larger, higher, and more pointed, 

 occasionally quite spinelike; in small specimens it is already sharp- 

 pointed and readilj^ hooks or engages a needle drawn backward along 

 the ischial border; in small as well as large A. uimguayana posteriorly 

 there is but a small low tuberclelike swelling or small nodulation 

 which often is relatively inconspicuous. 



Distrihution. — A. prado, so far as at present Imown, has been found 

 only in watercourses in and about the city of Montevideo. Dr. 

 Florentino Felippone, long a valued correspondent of the United 

 States National Museum, collected 2 males and 2 females of this 

 species in the Miguelete on December 6, 1922, along with four smaller 

 specimens of A. platensis. More recently, Alberto Tremoleras, son 

 of the late Dr. Juan Tremoleras, of Montevideo, Uruguay, kindly 

 collected for us a lot of 19 females in Arroyo Malvin, January 21, 

 1936, about 2 kilometers from its mouth. Of these, 16 were oviger- 

 ous specimens. He noted on the label, "fresh water, partly stagnant." 



AEGLA CASTRO, new species 



Figure 50 ; Plate 26, F 



Description. — A small species of which the largest specimen I 

 have seen measures 28.5 mm. in length of carapace and rostrum 

 together. 



Carapace moderately convex. Rostrum an elongate, triangular, 

 ridge-roofed spine, exceeding eyestalks by about li/^ times the length 

 of the cornea; rostral carina well defined, furnished with about two 

 rows of more or less alternating, often closely set, small, corneous 

 scales ; the rostral carina posteriorly merges with the general surface 

 of the carapace on a level with the protogastric lobes. 



Epigastric prominences somewhat rounded, blunt tuberclelike; 

 anterior margin of protogastric lobes forms a conspicuous obtusely 

 angled ridge or elevation which at its apex may be slightly scabrous. 



Orbit wide, orbital spines well set off from anterolateral spines by 

 a small to moderately wide extraorbital sinus. 



Anterolateral spine of carapace fairly slender, reaching to middle 

 of cornea or beyond. All three hepatic lobes usually plainly indi- 



