130 TEST ACE A ATLANTIC A. 



do, from the latter. Not only is the H. tceniata very much 

 larger, on the average, and more depressed* than the made- 

 rensis (the most highly developed examples measuring about 

 4-J- lines, instead of only about 3, across the widest part), but it 

 possesses an extra whorl (namely 8, instead of 7), its umbilicus 

 is appreciably wider and more spiral, its keel is considerably 

 more acute, and continued almost to the actual peristome, and 

 its volutions are extremely flattened, the basal one, moreover, 

 being granulated to a much greater distance from the aperture. 



The H. t&niata would seem to occur principally about the 

 cliffs, and rocky maritime hills, in the vicinity of Paul do Mar, 

 in the west of Madeira proper, where it was taken by Mr. 

 Lowe, on various occasions, in considerable abundance ; but it 

 does not appear to have been known, at any rate as a definite 

 form, either by Dr. Albers or the Baron Paiva, who merely 

 remark (the latter, evidently, having copied from the former), 

 in their observations under the H. maderensis ' Variat insuper 

 spira elatiore conoidea, et fere ["omnino," according to the 

 Baron] plana.' 



Neither does it appear to have been generally understood 

 that the present Helix (whether regarded as distinct from the 

 H. maderensis, or not) is, without any doubt, the H. tceniata, 

 W. et B., most unwarrantably admitted by Webb into the 

 Canarian fauna, with which it has clearly nothing to do. It 

 was originally detected, by Terver, along with the H. tiarella 

 (an equally characteristic Madeiran form), in some bags of 

 dried Orchil, the origin of which was even confessedly obscure ; 

 yet, so great was the desire of Mr. Webb to augment his very 

 meagre list that he seems, singularly enough, to have had no 

 scruple in quietly assuming both of these species, and that too 

 without so much as a fragment of evidence, to have come from 

 the Canaries ! thus importing an element of uncertainty into 

 the local catalogue which perhaps, however convinced we may 

 be of its injustice, can never be altogether eradicated. 1 



1 That Webb really knew next to nothing about the proper habitats of 

 these various Orchil-species of M. Terver's, some of which he seems to have 

 appropriated so ingeniously to augment his Canarian fauna, is evident from 

 an old letter of his, in my possession, which was written to Mr. Lowe, and 

 which bears the date 'Paris, Aug. 26, 1833.' Speaking of his ' Synopsis,' which 

 then had been just published, he says : ' At the end of our Synopsis you will 

 find an appendix containing some shells found in the Orchilla at Lyons, by a 

 most indefatigable collector Mr. Terver. Out of all he found,~tw0-r/mvfc tire 

 yours from Madeira and Porto Santo : but where the rest come from I know 

 not." 1 And yet a certain number of these very species are still cited in Mono- 

 graphs, on Webb's aiitlwrity, as ' Canarian ! ' 



Considering too that Mousson was equally satisfied concerning the un- 

 satisfactory nature of the evidence for the original admission of the //. 

 taniita and tiarella into the Canarian list, and considering also that he was 

 fully aware that the latter at any rate is a distinctively Madeiran species, and 



