276 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



flexuose, slightly entering, tongue-like, heavy callus, the basal margin with 

 a subraarginal obtuse stout denticle, right margin with a more deeply seated, 

 broader denticle. Greater diameter 9, lesser 8 mill. ; height, 3 mill. 

 Polygyra Troostiana, LEA, Tr. Am. Phil. Soc., VI. 107, PI. XXIV. Fig. 119 ; 



Obs., II. 107 (1839). TROSCHEL, Arch. f. Nat., 1839, III. 222. 

 Helix Troostiana, PFEIFFER, Mon. Hel. Viv., I. 419, excl. syn. et var. ; in 

 CHEMNITZ, ed. 2, I. 376, PI. LXV. Figs. 21-24. DESHAYES in FER., I. 75, 

 PI. LXIX. D, Fig. 4? REEVE, Con. Icon., No. 706 (1852). W. G. BINNEY, 

 Terr. Moll, IV. 88, PI. LXXVIII. Fig. 11. L. & Fr.-W. Sh., I. 98, Fig. 175 

 (1869). BLAND, Ann. N. Y. Lye., VI. 288, PI. IX. Figs. 21-23 (1858). 

 Helix fatigiata, BINNEY, Bost. Journ. Nat. Hist., III. 388, PI. XIX. Fig. 3, 



part, excl. syn. ; in Terr. Moll., part, II. 193, PI. XXXIX. Fig. 2. 

 Helix plicata, BINNEY (not of SAY), Terr. Moll., PI. XXXIX. Fig. 2, not text. 

 Dccdalochila Troostiana, TRYON, Am. Journ. Conch., III. 67 (1867). 



Murfreesboro', and Franklin County, Tennessee ; Kentucky. A species of 

 the Cumberland Subregion. 



P. Troostiana is very closely allied to P. fastigans, from which'I separate it 

 with some hesitation. In its fresh state it has a thin, sparingly hirsute epider- 

 mis. I have, moreover, two specimens in my cabinet (both hirsute), which are 

 as acutely carinated as fastigans, with the stria? as prominent below as above 

 (in one more numerous), but both having the parietal tooth of Troostiana. 



I am not altogether satisfied with the validity of Shuttleworth's remark, that 

 the superior tooth in fastigans is larger and more conspicuous than in Troosti- 

 ana. 



This species has the same tubercle within the last whorl as fastigans. 



Jaw as usual in the subgenus Polygyra, with about 10, broad, crowded ribs, 

 denticulating either margin. 



P. Troostiana (PI. VI. Fig. D) has 25 1 25 teeth, with 8 laterals on it3 

 lingual membrane. 



Genital system (PI. XV. Fig. I) long and slender, especially the ovary and 

 oviduct ; vagina long, receiving the duct of the genital bladder below its 

 middle, and the sac of the penis still lower down ; penis sac long, tubular, of 

 about same width as the vagina, with a prominent bulb at its apex, into the end 

 of which is inserted the vas deferens and at the side of which the retractor 

 muscle is attached ; genital bladder moderate, oval, on a duct of about equal 

 length and size as the vagina. 



Polygyra Hazard!, BLAND. 



Shell rimately umbilicated, discoidal, depressed above, convex below, light 

 horn-color, sparingly hirsute, with separated rib-like strise ; spire planulate ; 

 whorls 5 ; gradually increasing, the upper ones rounded, smoother, the last con- 

 vex, plane below, scrobiculated and with an insulated, smooth, prominent bulge 

 behind the peristome, deflected at the aperture ; rimation level, at first grooved, 



