278 FERUSSACIA, MADEIRA. 



Madeira: Ponta Sao Lourengo (M. Grabham . 



Twenty-four living specimens collected by Mr. Grabham 

 agree in differing from F. tcrebdla as above indicated, and 

 doubtless constitute a distinct race or species. It may, how- 

 ever, be what the Baron de Paiva attempted to define as A. 

 gracilis var. ventricosa. There is also a possibility that laurenti- 

 ana is what de Paiva alludes to as a more ample form of A. 

 leacociana, from this very place Sao Lourengo Point (Monogr. 

 Moll. Mader., p. 106). 



F. iridescens Woll. must be similar, but is described as con- 

 spicuously iridescent. No figure has been published, and the 

 diameter and length of aperture are not given by Wollaston. I 

 have therefore thought it well to suitably define and figure the 

 form from Sao Lourengo, leaving its ultimate status to be de- 

 termined when the characters of the several ill-defined forms 

 mentioned above are ascertained. 



71. F. GRACILIS (Lowe). PI. 39, fig. 20; pi. 40, fig. 32. 



"Shell long-obovate, slender, thin, glassy, glossy, smooth, 

 im perforate. Spire subattenuate, obtuse, more than half the 

 length of the shell. Whorls rather flattened, the suture rather 

 obsolete. Aperture obovate, toothless, columella broadly ex- 

 panded, slightly truncate, tapering into the thin, submarginate 

 lip. Length 2, diam. 1 line, whorls 5 n (Lowe). 



Length 4, diam. 1.8 mm. (specimen). 



Porto Santo: Common in some places in the mountains, type 

 loc. Pico Bran co ; also in the Grand and Southern Desertas. 



Helix gracilis LOWE, Trans. Cambr. Philos. Soc., iv, 1831, p. 

 61, pi. 6, f. 28. Achatina g., PFR., Monogr., ii, p. 284. 

 A. g., var. vitrea LOWE, P. Z. S., 1854, p. 200. Glandina 

 gracilis ALBERS, Malac. Mader., p. 56, pi. 14, f. 24, 25. 

 Lovea gracilis WOLL. , Test. Atlant. , p. 250. 



The name vitrea Lowe was applied to the typical form of 

 gracilis, as distinguished from several forms which Lowe con- 

 sidered varieties. 



I have copied on pi. 39, fig. 20, the figure of Albers, which, 

 however, is not very good, being too conic and acute. A typ- 

 ical example from the Wollaston collection is drawn on plate 



