1905 | ORTMANN— AFFINITIES OF CAMBARUS. 99 
of his C. dguett, which show, on the one hand, that C. carinatus 
Fax. is a synonym of this species, and-on the other hand, that the 
sexual organs have a rather peculiar shape. ‘The figures of these 
organs, given by Faxon (Pr. U. S. Mus., 20, 1898, pl. 63, f. 2 
and 3) are absolutely correct, but the description (p. 648) is rather 
short and unsatisfactory. Faxon says: ‘‘Inner and outer parts 
ending in asmall horny tooth, anterior margin furnished with a 
small tooth near the tip.’’ Fig. 2 represents this organ of the 
right side, seen from the outside: the outer part ends bluntly, 
without a distinct tooth, while the inner part ends in a rather 
pointed tooth, outside of which is a sharp spine that is longer than 
the outer part. Faxon’s Fig. 3 represents the identical part seen 
from the inside: only the two tips of the inner part are seen here, 
and the tip of the outer part is hidden behind the end of the inner ; 
the inner part is flattened and hairy on the inside, and the ‘‘ shoul- 
der’’ (‘‘small tooth near tip’’) is distinctly developed. My male 
specimen of C. digwe¢i agrees in every detail with the figures of Faxon. 
A very similar structure is seen in C. cubensis (Faxon, 1885, pl. 
7, f. 5), only here the flattened face of the inside is dilated, and 
the shoulder is more prominent. In both cases, there are practi- 
cally three tips to this appendage, ¢wo of which belong to the 
inner part. 
The description of this organ in C. mexicanus (Faxon, /. ¢., p. 
50) agrees closely, but possibly the ‘‘small, procurved spine’? at- 
tributed to the external part belongs to the internal, and then there 
would be complete agreement. 
The double tip to the inner part, and the shoulder, which has a 
very peculiar position, possibly give to these three species a more 
isolated position within this subgenus, and might possibly justify 
the creation of a separate subgenus, which then should stand at the 
head of the genus. This would also agree well with the geographi- 
cal distribution. 
Aside from these more primitive species (C. digueti, cubensis, 
mexicanus), the first section contains two others (C. s¢mu/ans and 
gallinas), which mark the transition to the third section, from 
which they differ only by the number of hooks of the male; the 
third section contains more advanced forms of the s¢wlans-type. 
The second section is a peculiar side branch going off from the first 
section, which has acquired burrowing habits; this is known posi- 
