MADEIRAN GROUP. 235 



(§ Alvearella, Lowe.) 



Pupa abbreviata. 



Pupa abbreviata, Lowe, Ann. Nat. Hist. ix. (1852) 

 „ „ Id., Proc. Zool. Soc. Lond. 213 (1854) 



„ „ Alb., Mai. Mad. 84 (1854) 



„ „ Paiva, Mon. Moll. Mad. 137 (1867) 



Habitat Maderam ; recens rarissime. In stratu conchyli- 

 fero ad Canical magis frequenter, tamen parce, semifossilis 

 occurrit. 



The present small Pupa, which appears to be almost unique 

 in a recent state, may be known by its short, broad, obtuse, 

 cylindric-oblong form, and by its rather closely but coarsely 

 costate surface ; and with the exception of the P. gibba it is 

 the only one of the strongly ribbed species which has the outer 

 lip externally sinuate, the denticle powerfully developed, and 

 the volutions (the basal one of which is, as in the P. gibba, 

 unusually short) not tumid. Its costse are oblique and slightly 

 flexuose ; its first ventral plait (which is united to the angle of 

 the lip by a thick corneous sphincter) is oblique and prominent, 

 the inner one is deeply immersed, and the upper one of its 

 (likewise very oblique) columella seems to be absent. 



The P. abbreviata, in a subfossil condition, is not very 

 uncommon in the calcareous deposits near Canical (where I be- 

 lieve it was first detected by myself ) ; but it has not been 

 observed, in the similar subfossiliferous beds, out of Madeira 

 proper. 



Pupa gibba. 



Pupa gibba, Loive, Ann. Nat. Hist. ix. (1852) 

 „ „ Pfeiff., Mon. Hel. iii. 552 (1853) 

 „ „ Lowe, Proc. Zool. Soc. Lond.213 (1854) 

 „ „ Alb., Mai. Mad. 69 (1854) 

 „ „ Paiva, Mon. Moll. Mad. 136 (1867) 



Habitat Maderam; et recens et semifossilis rarissima. 



This solid little Pupa is a trifle smaller, and still more 

 shortened or obtusely cylindric, than even the P. abbreviata, — 

 its outline being almost subquaclrate ; and its volutions are more 

 decidedly flattened, as well as more powerfully but more spar- 

 ingly costate. In the obliquity of its columella and plaits 

 (and therefore in the shape of its mouth), as well as in its 

 sinuated lip and its strongly developed, or internally prominent, 

 denticle, it is much the same as that species ; nevertheless its 

 two ventral plaits are very different from those of the P. abbre- 

 viata, — the outer one (which although rather close at its origin 

 to the angle of the lip, is nevertheless almost unconnected with 



