398 MEMOIRS OF THE CARNEGIE MUSEUM 
I think I have observed that in specimens from the south (Maryland and West 
Virginia) there is a more pronounced tendency to develop a second row of tuber- 
cles at the inner margin of the hand. Such specimens, with a few additional tuber- 
cles, occur also in Pennsylvania, but in West Virginia they are more frequent, and 
the additional row becomes more distinct and more regular. There is moreover a 
specimen from Parsons, W. Va., in which traces of a third distal row are visible. 
On the other hand specimens with one row only are also found in West Virginia. 
No interesting freaks or monstrosities have been observed. 
6. CAMBARUS (BARTONIUS) MONONGALENSIS Ortmann. 
(Plate B, Fig. 4. Plate XX XIX, Fig 4a, 4b and 10. Plate XL, Fig. 5.) 
Cambarus dubius Williamson, 1901, p. 11, (non dubius Faxon). 
Cambarus monongalensis Ortmann, 1905a, p. 395. 
Cambarus (Bartonius) monongalensis Ortmann, 1905d, p. 120. 
This species being closely allied to C. carolinus, the description will be given in 
terms of comparison with the latter. 
General shape of body, carapace, cervical groove, and areola identical with that in 
CNcaroliniuss Ges — e039 to tele wl alto less 
Rostrum (Pl. XX XIX, Figs. 4a and 4b) markedly different from that of C. caro- 
linus. It is as long as that of the latter species, or slightly shorter in the average, 
never reaching beyond the middle of the second joint of the antennula, and is uni- 
formly narrower. The upper surface is concave. The margins are less sharply 
elevated, the elevation decreasing gradually to the apex. Margins distinctly con- 
verging, and contracted to form the short, triangular acumen, but the contraction 
is not so sudden as in C. carolinus, so that the angles at the base of the acumen are 
not so sharp, but rounded. Acumen with short point. Postorbital ridges short 
and rather indistinct, distinctly divergent posteriorly. 
Sculpture of carapace and other details as in C. carolinus. The abdomen and telson 
are also identical, but the lateral corners of the anterior section of the telson have 
only one spine. 
Epistoma similar to that of C. carolinus, but the truncated (subquadrate) shape 
prevails in the anterior section, which has often a small median anterior point. 
Antenna and antennula similar to those of ©. carolinus, but antennal scale shorter, 
not much longer than the rostrum, and reaching only to the middle of the fourth 
joint of the antennal peduncle. 
First pereiopods (Pl. XL, Fig. 5) in general shape similar to those of C. carolinus, 
but hand not quite so broad, and there are important differences in the armature. 
The inner margin of the hand invariably has only one, but a distinct, row of tuber- 
