48 TEST ACE A ATLANTIC A. 



Habitat S. Miguel ; juxta Ponta Delgada parce deprehensa. 



This common and minute European Pupa was found both 

 by Morelet and Drouet in S. Miguel, — where in all probability 

 it must have been introduced accidentally, along perhaps with 

 consignments of shrubs and plants. It would seem to have 

 been found principally near Ponta Delgada, though Morelet 

 alludes to it also as occurring: in the Caldeiras. 



G-enus 12. BALEA, Pridx. 



Balea perversa. 



Turbo per versus, Linn., Fna. Suec. 2172 (1761) 

 Balea perversa, Pfeiff., Mon. Hel. ii. 387 (1848) 

 „ „ Loive, Proc. Zool. Soc. Lond. 215 (1854:) 



Alb., Mai. Mad. 69. t. 16. f. 15, 16 (1854) 

 „ nitida, Mouss., Viert. der Nat. Zurich, 168 (1858) 

 „ perversa. Morel., Hist. Nat. des Agor. 206 (1860) 

 „ „ Drouet, Faun. Agor. 167 (1861) 



„ „ Paiva, Mon. Moll. Mad., 140 (1867) 



Habitat ins. omnes (sec. Drouet) ; ad muros, in muscis, et 

 c£et., vulgaris. 



Morelet makes no particular mention of the exact range of 

 this common European Grastropod at the Azores, but Drouet 

 adds, more boldly, ' Habite tout I'archipel ' : and we have con- 

 sequently no option but to accept the latter statement (until at 

 all events it has been otherwise qualified or explained) as 

 literally and dogmatically true. It is therefore interesting to 

 feel assured that the B. perversa, which is so nearly absent 

 from the more southern Groups that it has been observed 

 hitherto only on the extreme summit of a basaltic mountain in 

 Porto Santo (where it was detected sparingly by myself), should 

 be absolutely abundant in the whole nine widely-scattered 

 islands which constitute the Azores. Such facts as these are of 

 great geographical importance, and we cannot be too thankful 

 to M. Drouet for having established so conclusively the Azorean 

 universality of this species. 



It would appear that the examples of this Balea from the 

 present archipelago are, on the average, a little more shining 

 than the ordinary continental ones, with their volutions a trifle 

 more tumid, and their aperture (which is just appreciably 

 smaller and rounder) free from a ventral plait ; and this cir- 

 cumstance induced Mousson to describe it as new, under the 

 name of B. nitida. It is the opinion, however, both of Morelet 

 and Drouet that these distinctions are not permanent ones, — the 

 individuals varying according to the districts in which they are 



