MADEIRAN GROUP. 211 



Pupa umbilicata, Drouet, Faun. Agor. 165 (1861) 

 „ „ Paiva, Mon. Moll. Mad. \20 {\SQ1) 



„ anconostoma, Mouss., Faun. Mai. des Can. 1 23 (1 872) 

 „ umbilicata, Watson, Journ. de Conch. 223 (1876) 

 Habitat Maderam ; in statu typico {i.e. Europaeo) a Eevdo. 

 E. B. Watson solum, ad Jardim da Serra, detecta. Sed status 

 aberrans (sc. P. anconostoma, Lowe, in ins. Maderensibus 

 Canariensibusque typicus), plica ventrali minore necnon peri- 

 stomate paululum minus expanso, ubique in inferioribus subin- 

 ferioribusque (prassertim cultis) abundat ; atque etiam in ins. 

 Desertis parce occurrit. 



After a careful comparison of the P. anconostoma, so uni- 

 versal throughout the lower regions of Madeira proper, with 

 examples of the European P. umbilicata, Drap., collected in 

 many countries widely separated from each other (as, for 

 instance, Portugal, England, Spain, and Sicily), I have come to 

 the conclusion that it cannot be regarded as more than a very 

 slightly altered phasis, or geographical variety, of the latter — 

 in which the ventral plait is (on the average) rather smaller or 

 less developed (and therefore usually more completely discon- 

 nected with the angle of the lip), and the peristome not quite ?,o 

 broad. All the other characters which have been alluded to, as 

 distinctive, in the various published diagnoses of the P. an- 

 conostoTYia, seem to me to be purely imaginary (as, for instance, 

 the smaller size, more cylindrical outline, and less tumid volu- 

 tions, referred to by Mousson, and the different shape of the 

 aperture recorded by the Baron Paiva) ; whilst even the ventral 

 tooth itself is subject to very great inconstancy, — it being much 

 larger in some of the examples now before me than it is in 

 others, in which case it is joined by almost as evident a callo- 

 sity with the angle of the lip as in the ordinary ones from more 

 northern latitudes. Amongst some specimens which were taken 

 by Mr. Lowe at Fayal, in the Azores, the two states are inter- 

 mingled, and pass imperceptibly into each other ; but those 

 from the Canarian archipelago correspond better with the ordi- 

 nary Madeiran ones, — both the tooth and the peristome being 

 less strongly developed. 



As expressed by this slightly altered form (which I would 

 consequently quote as the ' var. /3. anconostoma'), the P. um- 

 bilicata may be said to be the universal Pupa at low and inter- 

 mediate altitudes in Madeira proper, abounding about the walls 

 and cultivated grounds, and seldom ascending to higher than 

 about 2500 feet above the sea ; and it is not unlikely that it 

 may owe its presence there to accidental introduction at some 



(not very remote) period since the colonization of the islands. 



At any rate, apart from the suggestiveness of its distribution, 



p 2 



