400 TEST ACE A ATLANTIC A, 



cealed, and with its keel (which is more powerfully expressed 

 from the fact of there being a slight compression, or concavity, 

 on either side of it) very sharply defined. Its ground colour is 

 either white or brownish-white ; and it is ornamented with two 

 more or less conspicuous darker fasciae, one of which is placed 

 beneath, and becomes lost within the (acute, unthickened) aper- 

 ture, whilst the other is above the keel, and is broad and much 

 mottled or interrupted, occupying the volutions of the spire to 

 nearly its apex. The whorls themselves are, on the whole, flat ; 

 nevertheless the keel is distinctly traceable alongside the suture 

 up about two-thirds of the spire, which causes them to be a 

 little angular, or prominent, posteriorly. 



The nearest Canarian ally of the present species to the Te- 

 riffan H. phalerata, W. et B. ; but I think nevertheless that 

 the two cannot be treated as insular modifications of each other, 

 the tumulorum being very much larger and more obtusely 

 conical, as well as more strongly striated ; and its keel is sharper 

 and (as just mentioned) laterally compressed, and traceable up 

 the spire. The fascia, too, on the upper portion of the shell is 

 wider, it being generally suffused over the greater part of the 

 surface so as to give the latter a brightly speckled, or mottled, 

 appearance. 



In a subfossil condition the H. tumulorum occurs near to its 

 present habitat ; and I also met with it in calcareous places close 

 to the village of Puerta da Luz, which is but just removed from 

 the Isleta. 1 



Helix phalerata. 



Helix Eosetti W. et B., [nee Mich.], Ann. des Sc. Nat. 28. 



syn. 317 (1833) 



phalerata, Id., I. c. Append. 325 (1833) 

 Kosetti, d'Orb., in W. et B. Hist. 62. t. 1. f. 32-34 



(1839) 



phalerata, Pfei/., Mon. Hel. i. 158 (1848) 

 nivariensis, Shuttl., Bern. Mitth. 141 (1852) 

 Pfei/., Mon. Hel. iii. 167 (1853) 



phalerata, Lowe, Ann. Nat. Hist. vii. 106 (1861) 

 Mouss., Faun. Mai. des Can. 41 (1872) 



Habitat Teneriffam ; circa urbem Sanctse Crucis sublapidibus 

 vulgaris. 



It appears, according to d'Orbigny (who examined the types), 



1 In the Madeiran archipelago the nearest ally of the H. tumulorum is 

 probably the H. tectiformis, Sow., from Porto Santo ; nevertheless the much 

 greater bulk of that species, added to its large and open umbilicus, its over- 

 hanging, roof -like keel, and its coarsely granulated surface, will, apart from 

 coloration, at once separate it from all the members of the section Lenvniscia. 



