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 
DARE res iccean scl aecel esa spisieeio eeas Wile Scsldslcinviegeaissias eae Bartontus. 
Paracambarus stands very isolated within the genus. We 
have regarded Procambarus as representing to a degree the old 
original stock of the genus. Paracambarus is more closely 
related to Procaméarus 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, Paracambarus 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 
