MADEIUAN GROUP. 97 



vulgatissima. Necnon in solo arenoso semifossilis occurrit. 

 Var. 8. craticuata ad insulam ' Ilheo cle Ferro ' solum recens 

 pertinet ; sed in statu semifossili in Portu Sancto ipsissimo 

 late reperitur. 



This is one of the most abundant and universal of the 

 Helices of Porto Santo, — to which island, and the immediately 

 adjacent rocks, it would seem to be peculiar ; and it is tolerably 

 common in a subfossil state, — particularly under the phasis 

 which I have cited as the ' 8. craticulataj Lowe, which in a 

 recent condition occurs now only on the Ilheo de Ferro. 



The H. phlebophora may be known by its more or less 

 globose, strictly Helix-shaped, or subtrochiform, contour, and 

 by its variegated (or fasciated) surface, which is more or less 

 coarsely malleate and beset with oblique and very irregular sub- 

 confluent costate lines, — a peculiarity of sculpture which im- 

 parts a wrinkled appearance to the whole. 



The present species, however, passes through many degrees 

 of colour, outline, and sculpture, — the four principal ones being 

 [1] the normal state (corresponding with the ' a. chlorataf 

 Lowe), in which the shell is comparatively globose, and the 

 corrugations of the surface are more developed than the costse ; 

 [2] a more depressed form (answering to Lowe's '/3. planata '), 

 in which the spire is a little less raised, the surface, on the 

 average, a trifle paler and more variegated (the bands being 

 narrower, and more broken-up or interrupted), and in which 

 the oblique irregular costse are more sharply developed ; [3] a 

 yellowish-white, almost colourless or albino variety, free from 

 fascise and markings but otherwise agreeing with the ' a. 

 chlorataf Lowe, — and which represents the H. nivosa of 

 Sowerby ; and [4] a smaller, darker, and a more beautifully 

 dappled phasis, with the corrugations very coarse and large but 

 with the ridges almost obsolete, and with the spire relatively a 

 little more elevated, peculiar apparently (at any rate in a recent 

 condition) to the small islet known as the Ilheo de Ferro 

 (where it was first detected by myself), — and which was de- 

 scribed by Mr. Lowe in 1852 (under the name of H. craticulata) 

 as distinct, but which in 1854 he suppressed as a species, citing 

 it as the 4 var. 8. scrobiculata ' of the H. phlebophora. 1 



1 By a glance at the synonyms given above, it will be seen that in reality 

 Sowerby's name ' nivosa ' is the prior one for this Helix, by many years, — it 

 having been published in 1824, whereas Mr. Lowe's 'phlebophora ' did not 

 make its appearance until 1831. If therefore it be insisted that priority out- 

 weighs every other consideration whatsoever (even, for instance, the employ- 

 ment of a title which conveys an absolutely false idea of the species to which 

 it has reference), the change in the nomenclature must of course be made. 

 Under ordinary circumstances I should myself have made it ; but since the 

 name phlebophora has almost universally been allowed for this Helix, on 



II 



