MEXICAN, CENTRAL AMERICAN, AND CUBAN CAMBARI 3 



male generally with hooks on third pereiopods, rarely on third 

 and fourth pereiopods. 

 e. The two parts of the male organs shorter or longer, often very 



long, straight, divergent, or gently curved Faxonius. 



ee. The two parts of the male organs with rather short, sharply 

 recurved tips, forming about a right angle with the basal 

 part Bartonius. 



Paracambarus stands very isolated within the genus. We 

 have regarded Procambartis as representing to a degree the old 

 original stock of the genus. Paracambarus is more closely 

 related to Procambarns than to any other subgenus, but there 

 is no direct genetic connection imaginable. Although probably 

 derived from common ancestors, each has apparently gone its 

 own way of development, Paracambai'us being rather extreme 

 and one-sided in certain characters. 



The only species, upon which this subgenus is founded, is 

 new, and the description is as follows : 



CAMBARUS (PARACAMBARUS) PARADOXUS, 



new species. 

 Diagnosis : Rostrum subovate, slightly concave above, mar- 

 gins converging, without marginal spines, contracted into a 

 short, triangular acumen ; carapace without lateral spines ; 

 areola wide, slightly longer than half of the anterior section of 

 the carapace ; first pereiopods with the chela subovate, swollen ; 

 palm subcompressed, covered with strong, subsquamose tu- 

 bercles, which form, near the inner margin, two to three irregu- 

 lar, longitudinal rows ; fingers longer than the palm, with tu- 

 bercles at the bases, and a longitudinal rib on the outer faces ; 

 cutting edges with strong, irregular tubercles. Carpopodite 

 granulated and tuberculated, spinose on inner and lower side. 

 Only fourth pereiopods hooked in the male. First abdominal 

 appendages of male with both parts in close apposition to the 

 tips ; tips horny in the male of the first form, both with a slight 

 outward and backward curve ; inner part on posterior side, a 

 short distance from the tip, with a strong and long, spiniform 

 process. Annulus ventralis, of the female forming an almost 

 semicircular, transverse elevation, convex anteriorly, depressed 



