MADEIRAN GROUP. 267 



mark. And it was obtained by the Baron Paiva (who likewise 

 procured it from the Great Salvage), under a rather smaller 

 form, from the vicinity of Seissal. 



Grenus 17. AURICULA, Lam. 



After a careful examination of the Auriculas enumerated in 

 this volume, and a comparison of them with other species, it 

 seems to me that it is impossible to treat the two Sections under 

 one or the other of which they would usually be distributed 

 namely Marinula, King, and Alexia, Pfeiff. as in any sense 

 distinct from each other, the particular points which are sup- 

 posed, respectively, to separate them being not only in them- 

 selves extremely variable but often united with those which 

 characterize the opposite group. Thus the outer lip of the 

 aperture, which is denned as simple in the former but more or 

 less denticulated in the latter, is in the A. cequalis (which is an 

 undoubted Marinula] generally altogether unarmed, but never- 

 theless now and then thickened internally about the middle, 

 and sometimes to such a decided extent as to shape-out an ap- 

 preciable tooth, under which circumstances indeed examples 

 have been described as specifically distinct. Then, the solidity 

 of the shell, which is said to be less perfect in Alexia than in 

 Marinula, is often (as in the Alexia Paivana, Pfeiff.) quite as 

 great in the former as in the latter ; whilst the plaits of the 

 ventral paries are equally inconstant, as regards their number 

 and development, in both departments. Hence I shall not 

 attempt to regard the latter as having the slightest claim for 

 separation inter se, though I will add short diagnoses of the few 

 members of the genus with which we are here concerned in order 

 to render their specific details the more intelligible. 



Auricula sequalis, 



T. imperforata, fusiformi-ovata, solida, aut laevigata aut 

 basi lineis spiralibus plus minus obsolete impressa ; spira brevi- 

 uscula, conica, acuta, anfractibus 8 planis, sutura superficial! ; 

 apertura plicis 3 albidis instructa, sc. 2 (subsequalibus, aut po- 

 tius inferiore paululum majore, subparallelis) in pariete ventrali, 

 et 1 minore columellari spiraliter contorta ; peristomate recto, 

 acuto, marginibus callo tenuissimo politissimo junctis, columel- 

 lari reflexo dilatato albido. Long. lin. 4-5 ; diam. maj. 2-3. 



a. rufocastanea, nitidiuscula. 



?. [status normalis] plerumque paulo major, fulva, nitidi- 

 uscula. 



[7. (insulis Salvages propria, et forsan A. Ferminii, Payr., 



