488 FROCEEDESPGS OF THE NATIONAL MUSEUM vol. 91 



Orbital sinus moderately wide but shallow, orbital spine a small, 

 acute, corneous projection set close to the anterolateral spine and sep- 

 arated from it by a much-reduced extraorbital sinus, a small V-shaped 

 incision or notch. Anterolateral spine relatively short, flattened tri- 

 angular in the largest specimen, more slender and elongate appearing 

 in the smaller ones, may reach a little past the level of the posterior 

 margin of the cornea. 



First hepatic lobe, though separated from the anterolateral one by 

 a conspicuous notch, has its anterolateral angle bluntly rounded off 

 and its lateral margin small scabrous, as are the margins of the 

 second and third hepatic lobes, which are only poorly indicated; in 

 smaller specimens the first hepatic lobe is subacute and tipped with 

 a corneous scale larger than those elsewhere on the lateral margin. 



Hands broadly ovate, more or less flattened, yet gently convex. 

 Movable finger with a definite lobe on the outer margin near the base ; 

 lobe tipped or furnished with one or more acutely conical corneous 

 scales (almost very small, short, conical, corneous spines). Palmar 

 crest the most distinctive feature of this species, large, subdisciform, 

 and noticeably excavate, much as if it had been impressed or pinched 

 out while soft with the ball of one's thumb; margin of crest notice- 

 ably upturned, more or less obscurely serrate, scabrous to small- 

 spinulose. 



Eidge of carpus of cheliped above spined inner margin well devel- 

 oped, raised above general level of carpus, and marked with nodular 

 swellings carrying transverse rows of corneous scales ; anterior inter- 

 nal lobe or angle of carpus low, conical, and furnished with small 

 corneous scales apically and on its slopes. If one regards the largest 

 spine of those arming the inner margin of the carpus as the most 

 anterior of that particular series, we find then in this species on the 

 inner anterior slope of the base of that first spine a smaller, yet 

 conspicuous, strong spine located in more or less of a triangular 

 area delimited by that first spine, the carpal ridge, and the anterior 

 internal lobe of the carpus. This "inserted" spine may sometimes be 

 closer to, but not normally fused with, the large first spine of the 

 series arming the inner margin of the carpus than it is to either the 

 carpal lobe or the carpal ridge. This spine seems to be represented 

 in the closely related A. odebrechtii paulensis, immediately following, 

 by a similar one also placed on the anterior slope of the first spine 

 of the series arming the inner carpal margin ; unlike the independent, 

 distinct spine of the species proper {s. s. ) , it is always much fused with 

 the first spine (of the inner marginal series), so that usually only its 

 tip is distinguishable; sometimes it is wholly fused with the first 

 spine, which, in either case, is a very much thickened spine. In A. 

 odebrechtii, between the "inserted" spine as it may be designated and 



