W. H. Hudleston—The Yorkshire Oolite. 53 



Description. — Specimen from tlie Coral Eag of Ayton (my Collec- 

 tion). 



Length 6-5 milliinetres. 



Width 10 



Shell subglobular, smooth. Spire composed of about three 

 whorls, scarcely separated by any suture. The last whorl is enor- 

 mously larger than the preceding ones. Base convex and solid. 

 Aperture imperfectly preserved. 



Relations and Distribution. — The very great width of this shell in 

 proportion to its height, the flattening of the spire, and obsolete 

 character of the suture, whereby the entire shell seems almost to 

 consist of one whorl, serve to distinguish this species. On the 

 Continent no one but Buvignier records its presence, unless it is 

 concealed under some synonym. It is however closely allied to 

 Crossostoma discoideum, Morris and Lycett (Great Ool. Moll. p. 73, pi. 

 xi. fig. 7), and something very like it turns up on several horizons 

 in the Jurassic rocks. 



The dimensions of the specimen figured exceed those given by 

 Buvignier, but the proportions are about the same. Kare in the 

 Coral Eag of Ayton and neighbourhood. 



40. — Turbo (Monodonta) Erinus, D'Orbigny, 1847. Plate III. 



Figs. 5a, b. 



Turbo Erinus, D'Orbigny, 1847, Prod, de Pal. Strat. vol. ii. p. 9. 



Turbo inornatus, Buvigtiiei*, 1852, Stat. geol. de la Mouse, p. 37, pi. 26, figs. 27 



and 28. 

 Turbo Erinus, D'Orbigny, 1852, Terr. Jurass. vol. ii. p. 362, pi. 336, figs. 12-14. 



Bibliography, etc. — It would be a difficult and thankless task to 

 go closely into the history of this very average form. In the 

 Prodrome, D'Orbigny describes a species of Turbo from the Corallian 

 of St.-Mihiel as " wider than high, entirely smooth, whorls slightly 

 swollen, mouth round." In the Terrains Jui'assiques, the same 

 author gives the following dimensions for this shell, viz. length 

 11 mm., width 13 mm., spiral angle 90°. He regards the Turbo 

 Icevis ' of Buvignier (op. cit. p. 37, pi. 26, figs. 29, 30) as being the 

 same, but this is a much higher shell, having a spiral angle of lower 

 value. There can be very little doubt that the Yorkshire specimen 

 described below is the Turbo inornatus of Buvignier, but as the 

 description in the Prodrome, as far as it goes, is applicable, 

 D'Orbigny's name (Erinus) would seem entitled to priority, though 

 otherwise I should have preferred to adopt Buvignier's name. 



Description. — Specimen from the Coral Eag of North Grimston 

 (Strickland Collection). 



Length 12 miUimeti-es. 



Width 13-5 



Spiral angle 94^". 



Shell subglobular, wider than high. Spire composed of about 

 five whorls, which are smooth, convex, and fairly marked off by the 



^ Since D'Orbigny (op. cit. p. 362) qiiotes from the Statistique geologique de la 

 Mouse, it is clear that the date, 1850, prefixed to vol. ii. of the Terrains Jurassiques 

 is incorrect. 



