TURRICULA. 



349 



Fig. 232. 



Jaw of T. ttrrestris. 



TURRICULA, BECK. 



Animal hcliciform, mantle subcentral ; other characters as in Patula. 



Shell umbilicated or perforated, conical ; often obliquely costulate, banded 

 with chalky-white or of a uniform tawny color; whorls 5-10, rather flat- 

 tened, sometimes turreted, more or less angular or carinated ; aperture lunate, 

 narrow, peristome straight, its extremities thickened within. 



Jaw described with from 8 to 10 ribs. That of several French species is 

 figured by Moquin-Tandon. T. terrestris has 

 over 18 broad, flat, crowded ribs, slightly den- 

 ticulating either margin ; the jaw is low, wide, 

 slightly arcuate, ends but little acuminated, 

 blunt. 



Lingual membrane (of T. terrestris, from 

 Charleston, South Carolina) with 20120 

 teeth, the ninth tooth having its inner cutting 

 point bifid, centrals tricuspid, laterals bicuspid, marginals low, wide, with one 

 inner, long, oblique, bluntly bifid cutting point, and one outer, smaller, sharply 

 bifid (see PL XV. Fig. M). 



A genus of the circa-Mediterranean fauna, one species of which, T. terrestris, 

 has been introduced by commerce within our limits. 



Turricula terrestris, CHEMNITZ. 



Shell umbilicated, conic-roof shaped, white, above with delicate stria?, and 

 hardly unifasciate, flattened below ; whorls 6, flat, somewhat tur- 

 reted, narrowly carinated ; umbilicus very narrow, pervious ; aper- 

 ture axe-shaped ; peristome straight, acute, within thickened with 

 white. Greater diameter 10, lesser 9 mill. ; height, 6^ mill. 



Trochus terrestris, CHEMNITZ. 



Helix terrestris, PFEIFFER, Mon., I. 179. 



Found in Italy, Sicily, and South of France. I have lately received living 

 specimens collected by Mr. W. G. Mazyck in St. Peter's Churchyard, Charles- 

 ton, South Carolina, no doubt imported on plants. These specimens resemble 

 Moquin-Tandon's (PI. XX. Figs. 10, 11). 



Jaw arcuate, ends blunt, but little attenuated; anterior surface with 18 stout, 

 crowded, flat ribs. (See Fig. 232.) 



Lingual membrane (see above). 



Genital system, as figured by Moquin-Tandon, has a penis sac short, stout, 

 with a very long flagellate extension, on the middle of which enters the vas 

 deferens; the retractor muscle is. inserted at the commencement of the flagel- 

 lum ; the genital bladder is small, suboval, with a duct three times its length 

 and very stout ; at the entrance of this duct into the vagina there arc, on both 

 sides, a bundle of (four) multifid vesicles ; quite near the common orifice there 

 is a small, globular sac, enclosing in place of the usual dart a small body 

 fringed or digitated by four or five unequal obtuse lobes. 



Fig. 233. 



T. terrestris, 

 enlarged. 



