W. H. Hudleston—The Yorhshire Oolite. 51 



37.— Neritopsis Mokeauana, D'Orbigny, 1847. Plate III. Figs. 2a, h. 



JSferitopsis Mm-eauana, D'Orbia^ny, 1847, Prod, de Pal. Stat. vol. ii. p. 7. 



Idem. 1852, Terr. Jm-ass. vol. ii. p. 226, pi. 301, figs. 5—7. 



Bibliography, etc. — The original specimen was from the Corallian 

 of St.-Mihiel. We have already seen that Hebert and Deslong- 

 champs noted its relation to the foregoing species. 



Description. — Specimen from the Corallian of Yorkshire (Strick- 

 land Collection). The outer lip is too much broken away for accurate 

 measurement. Shell transversely oval. Spire very short and very 

 open, formed of two to three convex whorls which are wide apart. 

 Body-whorl immense in proportion, and rather rounded off at 

 either extreme, so as to give a truly convex character to the shell. 

 The ornaments consist of a double series of ribs closely set and 

 granulated at the nodes. In the transverse series of ribs there is 

 a slight tendency to unequal alternations. The longitudinal system 

 is somewhat the most prominent, and this feature is especially 

 noticeable in the penultimate whorl, where the intercostal spaces 

 are finely striated. 



The outer lip and anterior extremity of the shell are imperfect. 



Belations and Distribution. — Although the specimen in question 

 may not exactly correspond with the one originally described by 

 D'Orbigny, the diffei'ences would not warrant the making of a new 

 species. It obviously differs from Yorkshire specimens of N. Guerrei 

 in the general convexity of the whorl, in the fine and regular 

 ornamentation, and in the nodular character of the intersections. 

 The form would seem to be rare, as few authors allude to N. Moreau- 

 ana. 



As far as I know, Sir Charles Strickland's specimen is the only 

 one which has ever been found in Yorkshire. 



38. — Nekitopsis decussata, Miinster, 1844. Plate III. Fig. 1. 



Natica decussata, Miinst. , 1844, Goldfuss, pt. 3, p. Ill, pi. 199, fig. 10. 

 Neritopsis decussata, D'Orbigny, 1847, Prod, de Pal. Sti-at. vol. ii. p. 7. 



Idem, D'Orbigny, 1852, Terr. Jurass. vol. ii. p. 227, pi. 301, figs. 8-10. 



Nerito2}sts corallensis, Buvignier, 1852, Stat. Geol. de la Meuse, p. 81, pi. 22, figs. 



38—40. 



bibliography, etc. — Miinster's shell was from the Corallenkalke of 

 Nattheim in Wurtemberg. It has been identified by D'Orbigny 

 with a species of Neritopsis occurring in the Corallian of St.-Mihiel, 

 and if we may judge from the figure in Goldfuss the identification 

 is fairly warranted. I cannot see any difference between Miinster's 

 species, as identified by D'Orbigny, and N. corallensis, Buvignier, 

 from the Coralline Oolite of St.-Mihiel. Still Buvignier may not 

 have been satisfied with D'Orbigny's identification. There can be 

 little doubt that the Yorkshire shell under consideration answers to 

 the figures and description in the Terrains Jurassiques, and is the 

 shell identified in the Prodrome, whether the original identification 

 by D'Orbigny be correct or not. 



