276 TEST ACE A ATLANTIC A. 



where it abounds throughout Madeira proper in sylvan spots of 

 an intermediate elevation, — occurring on the ledges of the 

 rocks, and amongst loose friable soil and vegetable detritus, in 

 most of the damp ravines. It is extremely variable in hue (and 

 slightly so in sculpture,— there being sometimes faint indica- 

 tions of obsolete spiral lines, in addition to the conspicuous but 

 unequal transverse ones), — which ranges from a dark coffee- 

 brown.^ sparingly dashed with irregular patches of a pale straw 

 colour, into a greenish- or olivaceous-yellow, occasionally with a 

 leaden or even a decidedly blue tinge. 



Amongst the many varieties of this inconstant Crasi^edo- 

 poma, two were singled out Ijy Mr. Lowe, in 1860, as perhaps 

 specifically distinct, and were enimciated by him under the 

 names Jiavescens and neritoides. They seem to me, however, 

 to pass into the other states so completely that I cannot think 

 they possess the slightest claim to be separated as species, — the 

 jiavescens (in its extreme phasis) being merely a trifle smaller, 

 yellower, and thinner than the ordinary pallid type ; while the 

 neritoides (which is certainly a little more pronounced in its 

 peculiarities) has also a somewhat diminished stature, accom- 

 panied by a bluer surface, and a rather less rounded or ventricose 

 contour, the volutions being appreciably more flattened, and 

 the entire shell more compact and trochiform. But even this 

 latter aspect (namely the C. neritoides, Lowe) merges into the 

 other, unless I am much mistaken, by imperceptible gradations ; 

 so that I have no scruples in citing it as a mere variety, in con- 

 junction with the Jiavescens (which can hardly be defined as 

 even a ' variety ' at all). 



In a recent state the G. lucidum has not hitherto been ob- 

 served, so far as I am aware, out of Madeira proper (although 

 abounding in that island) ; but it occurs sparingly in a subfossil 

 condition both in Porto Santo and on the summit of the Southern 

 Deserta. In the former it was obtained by Mr. Lowe in the 

 calcareous deposits at the Fonte d'Areia, by myself at the Porto 

 dos Frades, and by the Baron Paiva on the Campo de Baixo ; 

 and I possess a single example of it from the Bugio. The 

 Porto-Santan specimens are rather small in stature, and might 

 pertain possibly to either the var. Jiavescens or the var. neri- 

 toides. In Madeira proper it is extremely common in the sub- 

 fossiliferous beds at Canipal. 



Craspedopoma Monizianum. 



Cyclostoma Monizianum, Loive, Ann. Nat. Hist. vi. 116 



(1860) 

 Craspedopoma Monizianum, Paiva, Mon. Moll. Mad. 158 



(1867) 



