258 A MANUAL OF AME'Mr.VN LAND SHELLS. 



The jaw of alternata, figured by Morse, is arcuate, equally broad in 

 Fig 274 ^^^ whole length, with square ends; anterior surface 

 stroDgly striate both transversely and vertically; con- 

 cave margin not strongly crenulated, but having no 

 Jaw of p alter ^^^^^^^^^^ projection. A specimen examined by me was 

 nata. much morc arched, with attenuated ends, strong median 



projection, and smooth anterior surface. 



Lingual membrane (Terr. Moll., V, Plate IV, Fig. E): One membrane 

 has 121 rows of 34-1-34 teeth, 10 of which are perfect laterals. The 

 variety mordax (Fig. F), agrees with it in dentition, except the nnmber 

 of teeth. 1 counted 20-1-20, with 8 perfect laterals. The change from 

 laterals to marginals is very gradual. 



The anatomy is given by Leidy (Terr. Moll., I, Plate YII, Fig. 2). 

 The genital bladder (15) is small, elongate-oval, on a long, delicate duct; 

 the penis sac (11) is short, stout, cylindrical, receiving the retractor 

 muscle (12) and the vas deferens at its apex. I have found a similar 

 genital system in the heavily ribbed form and in the var. mordax. 



Patula Cuiiiberlandiana, Lea. 



Shell broadly umbilicated, lenticular, acutely carinated, rather thin, 

 riG^275. sculptured with coarse, acute rib-strite, of a pale yellow- 

 ish or sometimes ash color, irregularly checked with 

 radiating, waved brown blotches; spire depressed, of 

 about 5 whorls, very slightly convex, but excavated 

 towards the margin, which is acute, and with a marginal, 

 p. cunib^ndiana. impressed line on both sides of the edge; beneath some- 

 what less convex, but the strisB less prominent, and its center excavated 

 by a deep, broad umbilicus, one-third the diameter of the base, and ex- 

 hibiting all the whorls to the apex; aperture rather wider than high, 

 rendered somewhat rhomboidal by the acute carina ; peristome simple, 

 acute, its columellar extremity somewhat dilated and reflected. Greater 

 diameter 15, lesser IS'""; height, 5'"'". 



CarocoUa Cumlcrlandiana, Lea, Trans. Am. Phil. Soc, viii, 229, pL vi, fig. 61; Obs., 



iii, 67; Proc, i, 289.— Troschel, Arch, fiir Nat., 1843, ii, 124.— De. Kay, N. 



Y. Moll., 47 (1843). 

 Helix Ciimberlandia)! a, Vfeiffkr, Mon. Hel. Viv., i, 125; iii, 114.— Binney, Terr. 



Moll., ii, 216, pi. xxvi.— Reeve, Con. Icon., 701 (1853).— W.G. Binney, Terr. 



•Moll., IV. 99; L. & Fr.-W. Sh., i, 76 (1869). 

 Anguispira Ctimherlandiana, Tryox, Am. Journ. Concli., ii, 262 (1866). 

 Patula Cmnierlandiana, W. G. Binney, Terr. Moll., v, 163. 



