SUCCINEA. 425 



of the two varieties differ much from each other, yet they are blended together 

 by almost inappreciable degrees of variation, and we have never met with 

 specimens in the Northern States which could not be referred to one or the 

 other of these varieties. 



Jaw of shape usual in the genus, with the quadrate accessory plate. Cut- 

 ting edge with a prominent median projection. Anterior surface with decided 

 stout ribs denticulating the cutting edge ; one specimen had three broad and 

 :wo intervening narrow ribs ; another specimen has seven ribs. 



Lingual membrane (PI. X. Fig. P) long and narrow. Teeth about 43 — 1 — 

 43. Centrals subquadrate, tricuspid, the middle cusp long and stout. Lat- 

 erals about 10, longer than wide, bicuspid, the third inner cusp being only ru- 

 dimentary. Marginals a modification^of the laterals, with one long, slender 

 inner cusp, and two short, slender outer cusps. The cusps of all the teeth 

 bear sharp cutting points. 



In Vol. I. PI. XIII. Fig. 3, a jaw is figured as that ot Succinea ovalis. It 

 no doubt represents rather that of the true obliqua, Say, than that of Succ. 

 ovalis, Gld. not Say. The jaw of the latter is figured in L. & Fr.-W. Shells of 

 N. A., I. p. 258. The figure of genitalia given by Dr. Leidy on the plate re- 

 ferred to correctly represents that of S. obliqua. 



The genital system is figured (under the name of S. ovalii) by Leidy, 1. c. 

 The testicle is not separated into distinct fasciculi by the parenchyma of (he 

 liver as in Helix, but forms a single mass ; the epididymis is very much convo- 

 luted, and appears always to be distended with spermatic matter; the prostate 

 gland is usually short, occupying the upper half only of the length of the ovi- 

 duct, and is thick, clavate, and more or less colored by pigmentum nigrum cells 

 upon the surface ; the penis sac is long, cylindroid, curved downward at its 

 upper part, and is joined at its summit by the vas deferens; the retractor mus- 

 cle is inserted into the penis sac a short distance below its summit ; the genital 

 bladder is large and globular, its duct is nearly as long as the oviduct, and is 

 narrow; the vagina is moderately long and muscular; the cloaca is short. 



It will be interesting to study the genitalA of other species o^* the genus in 

 order to ascertain whether the peculiarities of the testicle being free and the 

 prostate gland short are generic characters. In S. campestris the same arrange- 

 ment is found. 



Succinea Totteniana, Lea. 



Vol. III. PI. LXVII. b, Fig. 2. 



Shell obliquely ovate, of a greenish color, thin, shining, somewhat diapha- 

 nous, obsoletely striated ; whorls 3, convex, the last very large and globose ; 

 spire very short ; suture impressed ; aperture large, oval, oblique ; peristome 

 thin, acute. Greatest length, 16 mill. 



Succinea Totteniana, Lea, Proc. Phil. Soc, II. 32 (1841) ; Trans. Amer. PhiL 

 Soc, IX. 4 (1844); Obs., IV. 4.— Pfeiffer, Mod. Hel. Viv., II. 526; III. 



