1905.] ORTMANN — AFFINITIES OF CAMBARUS. 101 
4, Rostrum with marginal teeth. 
¢, Sexual organs of male with inner part not broadly dilated on inner 
side, curved forward at apex ; shoulder small. Rostrum carinated 
above. Carapace with lateral spines. 
C. (Cambarus) digueti Bouv. 
¢, Sexual organs of male with inner part greatly dilated, forming a 
broad, flat, setose plate on inner side; shoulder strongly developed. 
Rostrum not carinated. Carapace without lateral spines. 
C. (Cambarus) cubensis Er. 
6, Rostrum without marginal teeth, subplane above. Carapace without lat- 
eral teeth. Inner part of sexual organs flattened within, but not greatly 
dilated. C. (Cambarus) mexicanus Er. 
a, Sexual organs of male with two terminal teeth on outer part, one of which is 
flat and disk-shaped, inner part with one terminal spine; without shoul- 
der on anterior margin. Rostrum without marginal teeth (szmz/ans- 
group). 
6, Terminal teeth of sexual organs oblique, both of about the same length 
Acumen of rostrum longer. C. (Cambarus) simulans Fax. 
6, Terminal teeth of sexual organs straight, one much longer than the other. 
Acumen of rostrum shorter. C. (Cambarus) gallinas Cock. and Port. 
2. Section of C. gracilis (see p. 98). 
a, Rostrum suddenly contracted into a short acumen. Sexual organs with two 
teeth at end of outer part. Terminal spine of inner part straight, longer 
than outer part. 
6, Anterior margin of carapace forming a blunt suborbital angle. 
C. (Cambarus) gracilis Bund. 
6, Anterior margin of carapace not forming a suborbital angle. 
C. (Cambarus) hagenianus Fax. 
a, Rostrum triangular, margins not suddenly contracted to form an acumen. Sex- 
ual organs with only one compressed, triangular tooth at the end of outer 
part. Inner part straight, not longer than outer. 
C. (Cambarus) advena (Lec.). 
3. Section of C. blandingt (see p. 98). 
1. Group of C. spiculifer (see p. 100). 
a, Areola wide. Chelee rather broad. Two lateral spines on each side of the 
carapace. 
6, Chelee with large, remote tubercles. Margin of rostrum converging. 
Outer part of sexual organs with two terminal teeth. 
C. (Cambarus) spiculifer (Lec.). 
6, Chelze with small, crowded tubercles. Margins of rostrum subparallel- 
Outer part of sexual organs with three terminal teeth. 
. C. (Cambarus) versutus Hag. 
a, Areola wide or narrow. Chelz generally narrower. One lateral spine on 
each side of the carapace. 
6, Rostrum subplane above, ciliated. Areola wide. Outer part of sexual 
organs with two terminal teeth, the inner part with terminal spine di- 
rected outward. C. (Cambarus) pubescens Fax. 
