408 TEST ACE A ATLANTIC A. 



jt 



Habitat Fuerteventuram, Canariam Grandem, Teneriffam, 

 Gomeram, Palmam, et Hierro(in Lanzerota sola adhuc haud ob- 

 servata) ; late diffusa. 



The H. persimilis, Shuttl., which is probably universal 

 throughout the Canarian archipelago (Lanzarote being the only 

 island, out of the seven, in which it does not happen hitherto 

 to have been observed), is closely allied to the //. phalerata, 

 from which it seems mainly to differ in its smaller size, still 

 thinner substance, less strongly developed keel, and browner or 

 more suffused surface. It varies somewhat, however, not only 

 in size and the greater or less elevation of its spire, but likewise 

 in hue, occasional examples (as, for instance, a few which are 

 now before me from Hierro) being almost as brightly coloured 

 as the phalerata, or as the more variegated individuals of the 

 r/wnilifera ; and I must confess that I am quite unable to detect 

 any character to warrant the suspicion that Mousson's H. prce- 

 posita, which was established on a single example taken by 

 myself (in the Final of Tarajana) on the mountains of Grand 

 Canary, is anything more than a rather enlarged H. persi- 

 milis, by no means so much above the normal stature of the 

 species as is the more discoidal race from the maritime dis- 

 tricts of the same island which I have denned as a 'var. a. 

 umbilicata.' 



I have taken this variable shell, under its more typical phasis, 

 in Grand Canary, Teneriffe, Gomera, Palma, and Hierro, 

 my Teneriffan examples being principally from around Sta. 

 Cruz and Qrotava, and towards Taganana, and the Palman 

 ones from the district below Argual of the Banda ; and it ap- 

 pears to have been met with by Fritsch in Fuerteventura, Grand 

 Canary, Teneriffe, and Gomera, and by Blauner in Teneriffe 

 and Palma, 



The only aberrant aspect of the H. persimilis which seems to 

 be sufficiently constant to be worth placing upon record is one 

 which I would register as the ' a. umbilicataj and which was 

 obtained by Mr. Lowe and myself, on the dry submaritime 

 slopes both in the west and the south-east of Grand Canary, 

 namely on an exposed hillside (facing the sea) between Aldea 

 de San Nicolas and Lagaete, and in a somewhat similar situa- 

 tion between Maspalomas and Juan Grande. This particular 

 form is a trifle larger, less fragile, and more depressed than the 

 ordinary type, as well as more sharply keeled, and more con- 

 spicuously ornamented with two less-interruDted darker bands, 

 of which the upper one is broader and has the appearance 

 (from its being nearly continuous and unbroken) of almost ad- 

 joining the keel. The umbilicus too is appreciably larger, it 

 being more than a mere ' perforation.' In spite of this latter 



