GONOSTOMA. 



261 



Fig. 153. 



peristome thickened, somewhat reflected, white, not covering the umbilicus ; 

 internal laminae four, two upon the parietal wall of the aperture, of which 

 the upper one is much more developed than the lower; the two remaining 

 ones placed deep within the last whorl on its base. Greater diameter, 2h mill.; 

 height, l£ mill. 



Helix Hubbardi, A. D. Bkown, Proc. Acad. Nat. Sci. Philad., 1S61, 

 333. _\v~. G. Binney, L. & Fr.-W. Sh., I. 86 (1869). 



Strobila Hubbardi, Teyox, Am. Journ. Conch., II. 259 (1866). 



Helix Vendrijesiana, Gloyxe, Journ. de Conch., XI. 333, 1871. 



Found near Indianola, Calhoun County, Texas, Bonaventure 

 Cemetery, near Savannah, Georgia. It thus must have a wide 

 range over the Southern Region. It was subsequently discovered 

 at Bellevue, in the Parish of St. Andrew, Island of Jamaica, and 

 described as H. Vendryesiana. Gloyne mentions the parietal 

 lamella only, but there are others as described by Brown. The species is, in 

 fact, allied to .S'. labyrinthica, Say, and not to Polygyra paludosa, to which group 

 it is referred by Gloyne. 



The distribution of S. Hubbardi is certainly curious, but it may be observed 

 that S. Strebeli, Pfr., which is extremely like, if not identical with, labyrinthica, 

 belongs to the Mexican fauna. 



For jaw and lingual dentition (PI. V. Fig. N), see p. 258. 



Genitalia not observed. 



GONOSTOMA, Held. 



Animal as in Patula. 



Shell umbilicated, orbicularly depressed, arctispiral, often lightly hirsute ; 

 whorls 5-7, gradually increasing, the last angular or acutely carinated above ; 

 aperture oblique, narrow, lunate, quite often sinuous ; peristome reflected, 

 thickened, often heavy ; parietal wall without tooth-like processes. 



A European and Mediterranean genus, found also in the Canaries and at 

 TenerifFe. In North America it is only represented in the California Region, 

 and by one species only. 



Von Martens describes the jaw of Gonostoma as having distinct ribs. Moquin- 

 Tandon so figures that of obvolula, Mull., lenticula, Fe'r., and Rangiana, Fer ; and 

 Gassies (Journ. de Conch., XV. 186 7, 15) so de- 

 scribes that of //. constricta, B. Our single spe- 

 cies has a jaw (Fig. 154) low, wide, slightly arcu- 

 ate, ends scarcely attenuated, blunt ; cutting margin 

 without median projection ; anterior surface with a 

 strong transverse, line of reinforcement, and numer- 

 ous (about twelve) wide, crowded ribs de.nticulating either margin. 



The lingual membrane of obuoluta is described by Goldfuss (1. c. 45) with a 

 type of central teeth differing from that I have shown in Yalesi. This last hag 



Fig. 154. 



Jaw of G. Yatesi. 



