398 MEMOIRS OF THE CARNEGIE MUSEUM 



I tliink 1 have observed that in specimens from tlie 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. 



't> 



6. (Jambarus (Bartonius) monongalensis Ortmann. 

 (Plate B, Fig. 4. Plate XXXIX, Fig 4a, 4b and 10. Plate XL, Fig. 5.) 



C'ambarus dubins 'Williamsou, 1901, p. 11, (non tlubin^ Fa.xon). 



Cnmbmtis monongalensis Oitmann, 1905o, p. 395. 



Cambarus (Barlotiius) monongalensis Oitmann, 190.56, p. 120. 



This species being closely allied to C. cdiv/inus, the description will be given in 

 terms of comparison with the latter. 



General shape ofh(x1i/, carajiace, cervical tjroorc, and areola identical with that in 

 a caroHnns. G:H:B = 1: 0.9 to 1.1 : 1 .1 to 1.3. 



Rostrum. {F\. XXXIX, Figs, ia and 4//) markedly different from that of ('. caru- 

 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 (ioncave. 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 ('. car(ili)iiis, so that the angles at the base of the acumen are 

 not so sharp, liut I'ounded. Acumen with short point. Postorbital ridges short 

 and )-athcr indistinct, distiiutly divergent posteriorly. 



Sculpture of carapace and other details as in ('. caroVenvs. The alnJomen i\\\i\ tclsaih 

 are also identical. l)ut the lateral corners of the antei'ior section of the telson have 

 only one spine. 



Epistoma similar to that of (J. cawlinus, but the truncated (subquadrate) shape 

 prevails in the anterior section, which has often a small median anterior point. 



Anteniui and antennula similar to those of C. Carolina^, but antemied scale shorter, 

 not much longer than the rostrum, and reaching only to the middle of the fourth 

 joint of theantennal peduncle. 



Fifst pcreiopnjs (PL XL, Fig. 5) in general shape similar to those of C. carol inus, 

 but hand not quite so broad, and there are im])ortant differences in the armature. 

 The inner margin of the hand invariably has only one, l;)ut a distinct, row of tuber- 



