538 MR. &. A. SMITH ON THE GENUS ALABA. [Nov. 2, 
Of the species which he enumerates, 4. picta, A. cornea, A. 
felina, A. inflata, and A. phasianella, Angas (since described), have 
whorls smooth and not plicate or varicose, and the labium exhibiting, 
in A. picta only, but the faintest approach to a truncation, the colu- 
mella in the remaining species being rather straight, and generally 
blending into the labrum, which is slightly effuse at the base. 
Thus it will be seen that the characters assigned to the genus are 
not quite accurately applicable to all the species which have been 
included therein; and therefore I would propose the following divi- 
sions, which may somewhat facilitate their identification. 
Those species which have the whorls strengthened with varices 
(generally tumid) and the columella more or less (for this character 
is variable) truncated, will constitute the genus d/aba proper; and 
those devoid of the varices and wanting the columellar truncation 
may form the subgenus Diala, A. Adams, J. c. 1861, vill. p. 242, 
and 1862, x. p. 298. The subgenus Styliferina, A. Adams, J. ec. 
p- 299, is closely associated with the preceding group ; indeed there 
scarcely appear characters sufficient to warrant a separation. The 
chief peculiarity mentioned as distinguishing this form is in the apex 
*‘vertice mucronato ;”” but it does not differ to any material extent 
from that of several of the typical species. 
ALABA, 
Whorls tumidly varicose; columella more or less truncated ; 
labrum thickened in the adult state. 
A. vibex, A. Ad.; A. tervaricosa, C. B. Ad.; A. melanura, C. 
B. Ad.; A. supralirata, Carpenter; A. zebrina, A. Ad.; A. leu- 
costicta, A, Ad.; A. blanfordi, A. Ad.; A. puncto-striata, Gould. 
Subgen. Drara. 
Whorls not varicose (sometimes noduled around the middle ; 
columella straightish, not truncated ; labrum not thickened. 
D. lauta, A. Ad.; D. suturalis, A. Ad.; D. varia, A. Ad.; D. 
sulcifera, A. Ad.; D. picta, A. Ad.; D. pulchra, A. Ad.; D. im- 
bricata, A. Ad.; D. monile, A. Ad.; D. pagodula, A. Ad.; D. 
phasianella, Angas; D. (dlaba) tenuis, Smith ; D. cornea, A. Ad. ; 
D. simplex, Smith. 
Diala rufilabris, A. Ad., differs essentially from this genus in that 
the peristome is continuous, very much thickened everywhere, and 
the aperture oblique, the columella being consequently oblique also, 
and not more or less perpendicular as is the case in all the species in 
this group. Thus it will be seen that it should be removed to the 
genus Hydrobia. 
With the exception of A/aba puncto-striata, Gould, all the species 
above enumerated are represented in the British Museum, as are also 
those species described by P. P. Carpenter in the ‘Catalogue of 
Mazatlan Shells.’ But these, with one exception, I have purposely 
omitted ; for the mutilated condition of the specimens is such that 
it is impossible to say to what genus they (when perfect) may have 
belonged. 
