1905. ] ORTMANN —AFFINITIES OF CAMBARUS. 119 
3. Section: C. bartont. 
Carapace ovate, depressed, with or mostly without lateral spines. 
Rostrum without marginal spines. Chele comparatively short and 
broad, depressed, ovate. Areola wide or narrow, generally distinctly 
longer than half of the anterior section of the carapace, only in one 
case (C. acuminatus) slightly shorter than half of the anterior section. 
Leyes well developed. 
The four species belonging here are all closely allied to one 
another. ‘Their chief differences are furnished by the shape of the 
rostrum, width and length of areola, and shape of chelz: but all 
are built according to the same plan. 
4. Section; C. diogenes. 
Carapace ovate, compressed, without lateral spines. Rostrum 
without marginal spines. Chele short and broad, depressed, ovate. 
Areola very narrow or obliterated in the middle, always distinctly 
longer than half of the anterior section of the carapace. Eyes welt 
developed. 
The five species belonging into this section also form a very 
natural group. They are connected with the dartoni-section through 
C. latimanus (chiefly its var. strtatus Hay). The peculiar, com- 
pressed shape of the carapace (and possibly other characters, as 
shape of rostrum, narrow areola, shape of chelz) seems to be 
closely connected with the habits: all these species (it has of 
been reported for C. whlert but it is likely also the case with this 
one) are burrowing species and so-called chimney-builders. This 
habit begins to appear in the dartoni-section: C. bartoni often, but 
not always, makes burrows and chimneys, apparently forced to do 
so, when the water supply of the small mountain streams, in which 
it lives, begins to run short in dry seasons. With the species of 
this group, this habit becomes firmly established, and they never 
live without making burrows, having abandoned the streams and 
brooks, and taken to swampy and springy places, generally to the 
groundwater, where it is found at a short distance below the surface. 
The species of this section are distinguishable by the width of 
the areola, shape of rostrum, shape of the chelz, and in some cases 
by peculiar colors. I believe that it is the most highly specialized 
group of the whole genus, as is indicated partly by the burrowing 
habits, no doubt an extreme adaptation, and, in one species (C. 
uhlert), by the adaptation to brackish and salt-water, which is 
found: in no other case in the genus. 
