ALARIA ERINACEA. 61 



Alaria erinacea, 1 Piette. Plate VII, figs. 3, 4. 



1860. Bostellaria laevigata, Hcb. and Desl., Bull. Soc. Linn. Normand., vol. v, p. 11, pi. vi, fig. 10 



(non Morris aud Lycett). 

 1864. Alaria herinacea, Piette, Pal. France, t. Ill, p. 122, pi. xii, figs. 2 — 5 ; pi. xxxiii, figs. 1, 2. 

 1884. Alaria myurus, var. teres, Hudleston, G-eol. Mag. [3], vol. i, p. 197, pi. vii, fig. 4. 



Type. — " Shell fusiform, composed of 10-11 convex, rounded whorls, covered 

 with very fine spiral striae. The last whorl is doubly keeled and is gibbous on the 

 side opposite the wing. The posterior keel, which is the stronger, carries a spine 

 or rudimentary wing placed at equal distances from the wing and the gibbosity. 

 The young have no such spine. The suture is very pronounced. "Wing formed of 

 two digitations, whose curvature is unknown. Canal straight. The base is covered 

 with larger, alternating with finer, threads" (Piette) — Callovian, Montreuil Bellay. 

 Description — The specimen figured in PI. VII, fig. 3, is the same as that figured 

 by Hudlestou {Log. cit), and is still the only one known that preserves the ornament. 

 It agrees in all particulars with the above description and with the figures quoted, 

 except in (1) the presence of a gibbosity in the last whorl, which is apparently 

 accidental; (2) the occurrence of a spine before the lip is reached, which may have 

 existed when the shell was broken, or more, probably has not yet been developed ; 

 and (3) the finer details of the ribbing. On this latter point Piette states that 

 there are 23 lines on the penultimate whorl, of which 11 are large, alternating 

 with very fine ones ; the latter in some cases are wanting. Hudleston's description 

 of our present specimen states that " the furrows are narrow and shallow ; there 

 are about 20 on the penultimate, the intervening space being about three times the 

 width of each groove, and presenting a flat, strap-like appearance. One of the 

 straps towards the middle of the whorl is rather wider than the rest, but scarcely 

 more prominent. This represents the median keel." The earliest wdiorls look 

 very smooth, but the furrows gradually die out, and are ultimately masked by fine 

 lines of growth. The anterior canal also loses its ornament and becomes smooth 

 after a few alternate large and fine threads beyond the anterior band. It is certain 

 that both of these bands ended in a spine. 



Relations and distributio7i. — Hudleston considers this as " almost . . . anew 

 species" as compared with J. myurus, and that it is very near to the A. laevigata of 

 Hebert and Deslongchamps. These are just the two species to which Piette refers, 

 but he identifies the species with the latter instead of regarding it as a variety of 

 the former. It cannot be a variety in the strict sense of an Inferior Oolite species, 

 though it is probably a mutation ; but our form has changed more than Piette's. 

 The figured specimen is from the characteristic Cornbrash of Scarborough and in 

 1 The name is spelt by the author with an h, but presuming that the reference is to the " spine " 

 on one of the " keels " this is probably an oversight. 



