ALARIA BICORNIS. 63 



Alaria bicornis, sp. nov. Plate VII, fig. 6. 



1884. ? Alaria bispinosa, var. elegans, Hudlestou, Geol. Mag. [3], vol. i, p. 152, pi. vi, fig. 8. 



Type. — The similarity of this specimen to the one figured by Hudleston (loc. 

 cit.) as Alaria bispinosa var. elegans is such that the description, where it agrees with 

 this, will be given in inverted commas : " Approximate spiral angle 32°. Shell 

 turreted, somewhat elongate, the spire increasing with great regularity." The 

 spire as preserved consists of 10 whorls. " The earlier whorls are short, tumid, 

 and scarcely angular." The first 3, in addition to spiral lines, have about 12 

 coarse longitudinal ribs which absolutely disappear in the later ones, and these "are 

 ornamented with spiral lines of great regularity, one of which presently begins to 

 develop as a keel rather below the middle of the whorls, which in that part of the 

 spire immediately posterior to the body whorl become more angular, the upper 

 half projecting outwards to meet the keel, whilst the lower half is slightly con- 

 stricted. The spiral lines continue about the same in number but increase in size 

 with the increasing whorls. These keels are split by a very shallow spiral groove — 

 sutures close. The spiral lines in the anterior portion of the whorls are fewer and 

 wider apart than those in the upper portion. A similar style of ornament pervades 

 the body whorl, where a very sharp and prominent upper carina occupying a 

 median position is developed and a very subordinate anterior one. This upper 

 keel is prolonged into a very stout digitation " whose base extends backwards as 

 far as the keel of the penultimate whorl, and forwards into a broad glacis ; distally 

 it is grooved on the posterior side and curved into a backward hook. " There is no 

 trace of any digitation in connection with the anterior keel," which merely drives 

 out slightly the margin of the wing. The canal sheath or most anterior digitation 

 is at first nearly parallel to the axis of the shell, but soon forms a long curve in a 

 plane perpendicular to that of the posterior digitation, and downwards when the 

 latter is placed to the left. The upper part of " this portion of the shell is orna- 

 mented with spiral lines, which are rather finer than those of the spire." From 

 the sandy bed in the Woodstock Railway cutting at Shipton-on-Cherwell. In the 

 collection of Mr. Hudleston. 



Distribution. — The agreement with the type of the specimen described by 

 Hudleston from Scarborough in so many details, and the divergence only in parts 

 better preserved, show that it belongs here. It is of no use to compare our species 

 with the " Rostellaria bispinosa" of Phillips; that name is not sufficiently char- 

 acterised and can only serve as a group name. It is not even certain whether the 

 specimens so named were bispinose or trispinose. It would appear, however, that 

 all the records of A. bispinosa refer to the single specimen here referred to. 



Relations. — The characters of the spire not being very remarkable, almost any 



