136 THE NAUTILUS. 
nearly always present, but on the Ilheo de Baixo, on Jan. 22, I 
found a creamy-white bandless variety, which may be called 
var. lactescens. This form was also known to Wollaston. The 
distribution of H. punctulata is peculiar. It has not been re- 
corded from Madeira, but a rather small and peculiar race 
(avellana Lowe) occurs both living and fossil on Bugio, the 
southernmost of the Desertas. At the fossil-beds near Canigal, 
Madeira, however, I found a specimen of undoubted P. punctu- 
lata, measuring 13 by 14 mm., thinner than bowditchiana, and 
still showing faint traces of the bands. It has a recent appear- 
ance, and may not be truly fossil. Whether P. punctulata really 
lived in Madeira, may still remain somewhat uncertain, as 
Baring and Ogilvie Grant (Zoologist, Nov. 1895) report finding 
seven whole H. pisana in the stomach of a kestrel, and it is 
conceivable that an owl pellet might contain an unbroken snail 
shell. 
The P. punctulata in Porto Santo suffer severely from an 
enemy, the broken shells being found very commonly under 
rocks. From the position of these remains, it was impossible 
that the enemy should be a bird, and thesmall lizards (Lacerta 
dugesii) so common under the rocks probably could not break 
the shells. Baring and Ogilvie Grant (loc. cit.) speak of the 
great spider of Porto Santo (Lycosa madeirana Walck.) as feed- 
ing on snails, and I have no doubt that this is the mysterious 
enemy of P. punctulata. In the face of such an enemy, P. bow- 
ditchiana, with its large and thick shell, would have a great ad- 
vantage over its smaller relative. 
The common P. vulgata (Lowe) of Madeira has the same 
white mantle, and is evidently strictly congeneric. According 
to Pilsbry this is the real nitidiuscula of Sowerby, though not 
that of Wollaston. The soft parts of vulgata from Funchal were 
described as follows : 
Animal with foot broad, white ; tentacles black ; dorsal side 
of head and neck very dark, abruptly contrasting with the 
white foot ; mantle opaque white. The habits of vulgata seem 
to be much like those of punctulata, though it is perhaps less 
retiring. There is a large Lycosa (L. blackwailii Johnson) in 
Madeira, which may prey upon it but it seems to be absent from 
the lowlands about Funchal, where P. vulgata abounds. 
