FERUSSACIA, MADEIRA. 279 



40, fig. 32. Wollaston remarks that ' ' As thus limited, there- 

 fore, the L. gracilis may be known by its small size and some- 

 what slender outline, by its extremely thin, almost colorless, 

 and transparent substance, and by its rather wide (or expanded), 

 but nevertheless simple (or basally untruncate) arcuated colu- 

 mella. Although it has been found sparingly (as just stated) 

 on the two Southern Desertas, it is a species which is more 

 particularly characteristic of Porto Santo, where I have met 

 with it in profusion, beneath stones, on the exposed mountain 

 ridge which connects the Pico de Facho with the Pico do 

 Castello. Mr. Lowe's original examples, however, were from 

 the Pico Branco " (Wollaston). 



Subgenus PYRGELLA Lowe. 



Pyrgella LOWE, P. Z. S., 1854, p. 205, type and sole species 

 A. leacociana. 



Shell turrite-oblong, thin; aperture short, less than half the 

 total length, ovate, the outer lip in profile very strongly arched 

 forward, retracted above, not calloused inside; parietal wall 

 smooth; columella slightly twisted. Type F. leacociana. 



This form seems to be more closely related to Cylichnidia than 

 to any other group, although it is without apertural lamellae or 

 callosities. The Pyreneean Cryptazeca has some resemblance to 

 Pyrgella. 



72. F. LEACOCIANA (Lowe). PI. 39, figs. 26, 27. 



The shell is very small, oblong-turrite, widest near the base, 

 very thin and fragile, subtransparent, yellowish-corneous, 

 glossy, with a very narrow gray subsutural margin edged below 

 with a light line. The spire has slightly convex outlines and 

 obtuse summit. Whorls 5, slowly widening to the last which 

 descends more rapidly. The aperture is small, piriform, very 

 narrow above. Outer lip thin, strongly arched forward in the 

 middle, deeply excised or retracted to the suture above. Colu- 

 mella rather wide, projecting into the aperture, truncate at base. 

 Length 3.7, diam. 1.6, length of aperture 1.5 mm. 



Madeira: Near Funchal in the Ribeira de Joao Gomes (type 

 loc. ), and near the Levada da Senhora do Bom Successo; in the 



