152 TEST ACE A ATLANTIC A. 



with transverse subeonfluent lines, which are more or less inter- 

 rupted (or broken up) into elongated granules. Its colour is 

 reddish-brown above, and rather paler beneath, — the umbilical 

 region and the portion of the basal whorl outside the aperture 

 being gradually more or less ochreous ; and there is a narrow 

 and generally obscure, medial fascia both above and below the 

 keel. The peristome is a good deal thickened internally, and 

 there is a more or less evident white callosity (sometimes obso- 

 lete) within the aperture on the ventral wall. 



Like so many of the Helices^ the H. rotula has occasionally a 

 well-nigh colourless, albino state ; and sometimes the volutions 

 are unnaturally extended or drawn-out, causing the keel (as it 

 were) to overhang the suture and to be conspicuous up the spire. 



In a subfossil condition the H. rotula is decidedly rare, 

 nevertheless I have taken it in the calcareous deposits at the 

 Zimbral d'Areia, 



(§ Caseolus, Lowe.) 



Helix consors. 



Helix consors, Lowe, Carahr. Phil. S. Travs. iv. 51. t. 6. 

 f. 3 (1831) 

 „ Pfeif., Mon. Hel. i. 195 (1848) 

 „ „ Loive, Proc. Zool. Sac. Lond. 184 (1854) 



„ „ Alb., Mai. Mad. 41. t. 10. f. 23-25 (1854) 



„ „ Paiva, 31 on. Moll. Mad. 38 (1867) 



Habitat Portum Sanctum ; in montibus vulgaris. Semi- 

 fossilis vulgatissima. 



The H. consors is peculiar to Porto Santo, where it is one 

 of the commonest of the Helices, — abounding, however, still 

 more in a subfossil than in a recent state. The subfossilized 

 specimens are, on the average, rather smaller than the recent 

 ones ; and they are consequently difficult at times, from their 

 colourless and decomposed condition, to distinguish from those 

 of the H. compacta, though in a general way they are pretty 

 easily separated. 



The whole of the members of this immediate type are solid 

 in substance ; and, although more or less strongly sculptured, 

 they are perfectly bald, — having no tendency whatever to be 

 hispid or pilose ; and the H. consors, calculus, and compacta. 

 are somewbat globose and compact in outline, altogether un^" 

 keeled, and with a very small and punctiform perforation, — 

 which is a trifle further removed from the recurved margin of 

 the peristome in the last of those species than it is in the first 

 and second. The H. consors is, however, on the average, very 

 much the largest of the three (highly developed examples mea- 



