1892.] LAND-SHELLS OF ST. HELENA. 263 



tenui prominenti in medio palati) instructa ; peristoma tenue, 

 marginihus remotis, columellari leviter dilatato. 



Longit. 2| millim., diam. 3^ ; apertura I5 longa, | lata. 



Hah, Fiagstaif Hill {E. W. Alexander). Extinct. 



This species has the spire more elevated and conical than the 

 other species of Patula from the island. P. cutteri, Pfr., may 

 approach it somewhat, but that species is said to have only two 

 parietal lamellse, and two basal denticles near the. columella. The 

 present species has an additional basal denticle, and a prominent thin 

 palatal lamella, which falls as it were between the two on the inner 

 or parietal side of the aperture. 



10. Patula cutteri (Pfeiffer). 



Hab. Diana's Peak. Living (Pfr.). 



A small species, unknown to me, apparently similar in general 

 features to the preceding, but with only four teeth within the 

 aperture, two parietal and two basal near the columella, more 

 narrowly umbilcated and probably more strongly sculptured. 



11. Patula polyodon (Sowerby). (Plate XXI. figs. 8-8 c.) 



This is the most widely umbilicated of all the species 0^ Patula from 

 St. Helena, and this feature alone is sufficient to distinguish it from 

 the rest. The whorls also, in adult shells eight to nine in number, 

 enlarge very slowly. The strige are fine, regular, arcuately oblique 

 above, and slightly wavy on the last whorl. There are three parietal 

 lircB extending far within the aperture, of which the upper and 

 lower are nearly always double. The plicse within the outer lip 

 are almost invariably (in adult shells) seven in number, subequi- 

 distant, but not of equal thickness, two or three towards the 

 columella being stouter than the rest, which are slender and extend 

 some distance within. 



Diam. maj. 5 5 mill., miu. 5, alt. 2^. 



Hab. Side Path, Sugarloaf Quarry, Sugarloaf Ridge {Turton), 

 Extinct. 



The species to which the foregoing remarks apply is certainly the 

 Helix alexandri of Forbes, for in the British Museum there are 

 specimens of it presented by Mr. Alexander, who also furnished 

 Forbes with the shells he described. Moreover the description is 

 fairly applicable, especially that portion of it referring to the 

 umbilicus, which is described as " marcimus." It is much less 

 certain that this is the H. polyodon of Sowerby, but as Mr. Wollaston 

 has united these species as well as H. helenensis (Forbes), Pfeiifer, it 

 will probably be advisable to acquiesce in this decision. There are, 

 however, certain differences in the descriptions, which seem to indicate 

 that more than one species was described by these authors, for 

 instance s — H. polyodon is said to consist of six striated whorls, with 

 three parietal and five palatal lirse, and a moderate-sized umbilicus, 

 whereas H. alexandri is described as having seven strongly striated 

 whorls, three parietal and eight palatal lirae, and a very large 

 umbilicus. H. helenensis is characterized as possessing eight very 



