466 



PROCEEDINGS OF THE NATIONAOL MUSEUM 



denticulated convexity on margin in line with spine at anterior end 

 of dorsal longitudinal ridge. Inner margin of ventral surface of 

 ischium not spined, at most with only a low swelling at anterior end, 

 and perhaps a very slight convexit}' at posterior end. 



Anterior dorsal angle of epimeron of second (in lateral view, ap- 

 parent first) abdominal somite produced to form an acute corneous- 

 tipped spine buttressed behind by a blunt ridge or thickening of 

 epimeron ; anterior margin below spine more or less straight, at most 

 only slightly concave ; ventral angle rounded off. 



Figure 46. — Aegla platensis, new species, male paratype. Natural size. 



Holotype—T\iQ largest male, U.S.N.M. No. 80018, from a lot of 

 2 males and 2 females collected at "Isla Flores" [? Tigre, Buenos 

 Aires, Argentina] by Dr. W. E. Safford, U. S. N., at the time attached 

 to the U. S. S. Mohican, May 4, 1887. This specimen measures 

 slightly over 38 mm. in length of carapace and rostrum together; 

 the largest female is 33.5 mm. long. 



Remarks. — This species and the next are in many respects very 

 similar. They differ, however, in a number of particulars. The 

 movable finger in this species has a lobe on the outer margin near 

 the base; no such lobe seems ever to be developed in any specimen 

 of A. Uruguay ana, male or female; moreover, in case of doubt, the 

 presence of a well-developed sharp spine at the anterior end of the 

 inner border of the ventral surface of the ischium of the cheliped 



