156 TEST ACE A ATLANTIC A. 



• vav. /3. pusUla ' of this species; though I am not at all satis- 

 fied that it would not be far more natural to treat it as distinct. 

 Still, as it appears to bear someii'/mf the same relation to the 

 normal //. com/mixta that the ' var. h. pusiUa* of the H. com- 

 pacts does to that species, I am content to cite it as Mr. Lowe 

 has done, — even whilst feeling extremely doubtful as to its real 

 specific identity with the commixta. In point of fact it would 

 be scarcely separable from the ' 8. pusilla ' of the H. compacta, 

 were it not that it is powerfully and conspicuously granulated 

 both above and below. Whether properly referred however to 

 the H. commixta or not, it is a form which is extremely abun- 

 dant in most of the calcareous deposits of Porto Santo. 



So far as I can at present recollect (for I unfortunately 

 made no particular memorandum, at the time, of their exact 

 habitat), I believe that it was on the Ilheo de Baixo that my 

 specimens of the H. commixta were principally found. 1 



Helix abjecta. 



Helix abjecta, Lotve, Cambr. Phil. S. Trans, iv. 50. t. 6. 

 f. 1 (1831)' 

 „ candisata, Menke, in Pfeiff. Symb. iii. 70 (1846) 

 „ abjecta, Pfeiff., Mon. Hel. i. 188 (1848) 

 „ „ Loive, Proc. Zool. Soc. Lond, 185 (1854) 



„ „ Alb., Mai. Mad. 32. t. 8. f. 1-8 (1854) 



„ „ Paiva, Mon. Mull. Mad. 42 (1867) 



Habitat Maderam, Portum Sanctum, Desertam Australem, 

 et (sec. Paiva) Desertam Grandem ; in Portu Sancto solum 

 vulgatissima. SemifossUis in Portu Sancto copiosissime, sed in 

 Madera ad (sec. Paiva) Canical rarissime, occurrit. 



If the Baron Paiva's statement may be trusted, that he has 

 received it from the Deserta Grande, the H. abjecta (however 

 scarce beyond Porto Santo) will have been found in all the 

 islands of the Madeiran Group except the Northern Deserta (or 

 Ilheo Chao). Throughout Porto Santo, and on the immediately 

 adjacent rocks, it absolutely swarms ; but it is singular that 



1 The Baron Paiva has wonderfully confused this by no means badly de- 

 fined Helix. In fact he evidently did not know it, practically; though some 

 of his recorded characters were copied clearly from Mr. Lowe's diagnosis. 

 Thus he cites it as the depressed variety of the H. abjecta (which, as above 

 mentioned, it most decidedly is not) ; then he asserts it to be a subfossil form, 

 whereas the H. corwmixta is a living one and has not as yet been observed at 

 all (as typically defined) except in a recent state; and he lastly adds that it 

 occurs likewise on the Southern Deserta, whereas the species from that island 

 is a scarcely altered phasis of the genuine H. abjecta ' In real truth, in its 

 general contour and rather widened (or, as it were, super-imposed) ultimate 

 volution, no less than in its more circular and raised peristome, the H. com* 

 ytixta makes a very manifest approach towards the Hystricella group, 



