ALARIA. 121 



41. Alaria pusoa, sp. nov. Plate V, fig. 3. 



Description : 



Approximate length . . . .26 mm. 



Width of body- whorl to length of shell . . 48 : 100. 



Spiral angle . . . . .38°. 



Shell turrited, subelongate, apex blunt. Number of whorls about 10 ; the two 

 apicals rounded and without ornament ; whorls of the spire tumid and subangular, 

 keel median and becoming very prominent in the anterior whorls. Longitudinal 

 costse numerous, close, slightly curved, and extending nearly from suture to suture, 

 being equally well-developed on the posterior as on the anterior area ; spiral striaB 

 regular, numerous, and nearly uniform ; sutures distinct and bordered by a slightly 

 raised rim. Body- whorl without costge ; posterior keel enormously developed, 

 anterior keel barely perceptible. 



Wing single, with a deep and strong digitation, extending at right angles to 

 the axis of the spire for about three-fourths the length of the spire, where it forms 

 a very thick elbow, and then turns up in the shape of a short hook ; the digitation 

 is finely marked by lines in continuation of the spiral ornament of the shell. Other 

 indications wanting. 



Relations and Distribution. — Differs from Al. hamus in the shape of the whorls, 

 which are less mural, in the more median position of the keel, and in the fact that 

 the costse extend nearly from suture to suture. In this species the posterior keel 

 is more salient, and the anterior keel less developed. The length of the digitation 

 and its great thickness at the elbow are also differences, so far as we can judge, 

 from the few specimens which have these processes preserved. On the other hand, 

 the shell is by no means wanting in a general resemblance to Al. Dundryensis, 

 though unfortunately we are ignorant of the character of the wing in Mr. Tawney's 

 species. 



Alaria fusca is extremely rare in the Gadomensis-bed at Oborne (upper part of 

 the Humphriesianus-zone). 



42. Alaria. Species or variety. Plate V, fig. 4. 



There is hardly justification for burdening our lists with a fresh name in the 

 present instance. This may possibly be the Dorsetshire representative of Al. 

 Dundryensis, to which it bears considerable resemblance in the character of the 



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