THE SPECIES OF AEGLA — SCHMITT 451 



fan. In the female the abdomen as a whole is relatively shorter and 

 broader than in the male, and the median dorsal area of the respective 

 abdominal somites is relatively wider. This character usually enables 

 one superficially to distinguish males from females. The sexes, how- 

 ever, are definitely distinguished by means of their genital apertures. 

 In the female these open on the coxopodites of the third (antepenulti- 

 mate) pair of legs, and in the male on the fifth (last) pair of legs. 

 In mature males the vas deferens on each side is externally produced 

 as a thin- walled tube. 



KEY TO THE SPECIES OF AEGLA 



A*. Rostrum definitely ridge-roofed," triangular in cross section ; above, with 

 lateral slopes of "roof" running down often at nearly a 45° angle from 

 median carina to lateral margins (these lateral slopes are not distinctly 

 troughed or excavate either side of the median carina as are practically 

 all the relatively flattened rostra of the species under A-, p. 454 ; at most the 

 lateral rostral slopes may be slightly concave) ; rostrum sometimes show- 

 ing a slight upward inclination toward tip, but usually straight and 

 not recurved ; rostral carina and scales with which it may be furnished 

 running straight and usually definitely to anterior extremity; front of 

 species belonging to this section of key generally wide or at least moder- 

 ately wide, rarely somewhat narrowed (as in jujuyana and franca) ; 

 orbital spines well developed; sinus (extraorbital) between orbital and 

 anterolateral spines generally of good size, wide or moderately wide, rarely 

 small (jujuyana, franca, and occasional specimens of prado). 

 B^. Hands, though they may become somewhat thick and swollen, never taking 

 on markedly inflated or subglobular appearance of jujuyana {B\ p. 453) ; 

 inner margin of palm always more or less crested, and when crest is low 

 and little developed armed with at least one sharp spine at anterior end ; 

 lobular tooth on at least fixed finger usually present and well developed ; 

 rarely is this tooth not definitely present, or obsolescent, as in A. san- 

 lorenzo (p. 452) (lobular tooth on fixed finger is also lacking in jujuyana, 

 B', p. 453, and humaliuaca, under section A", p. 456 of this key) ; dorsal 

 anterior angle of epimeron of second (in lateral view, apparent first) 

 abdominal somite almost always armed with a spine (sometimes not in 

 franca) . 

 C\ Front generally very wide, extraorbital sinus at least half, usually more 

 than half of, to nearly subequal to orbital sinus (somewhat nar- 

 rower than other species in this section is sanloremso) ; orbital spines 

 a prominent feature of frontal margin. 

 D\ Posterior margin of ventral surface of first ambulatory merus armed 

 with at least one conspicuous strong spine near distal end about on a 

 level with proximal border of articular membrane"; inner margin 

 of ventral surface of ischium of chelipeds armed with two fairly 

 long, well-developed, acute, corneous-tipped spines, one near distal 

 end of joint, the other near proximal end (spines of this size and 



» In lateral view at the level of the anterior margin of the cornea, the height of the 

 rostrum, or its carina, above the lateral margin of the rostrum is usually much greater 

 than the depth of the rostrum below the lateral margin. 



'^° A. prado has a spine of moderate size in this position and A. castro a quite small one 

 or two, but both are species with the front only moderately wide, (P, p. 453, this key. 



