APPENDIX. 15 



continued and successful researches. The species was first described and figured by myself from the 

 Upper Lias of May, near Caen, and subsequently again by M. Eugene Deslongchamps. In external 

 shape, it reminds us of several Cretaceous Thecidiidae, such as Th. tetragonum, Roemer, Th. rugosum, D'Orb., 

 &c, but is distinct from either, by the more simple internal arrangements of the smaller valve, where none of 

 those numerous sinuated ridges exist; and it is certain, from the recent discoveries made, both by MM. 

 Suess and Deslongchamps, that this and other Liasic Thecidiidce possessed a more complicated internal 

 structure than that exhibited in the generality of specimens in which many delicate portions are destroyed. 



PI. a., fig. 6. A specimen from the Leptsena bed, near Ilminster. 6 "•*•'■ enlarged representations. 



Mr. C. Moore has also discovered three or four species of Thecidhanio. the sands of the Inferior Oolite at 

 Dundry. 



Page 16, Leptcena. 



Since the publication of the first Liasic species, many beautiful examples have been discovered in other 

 localities. In 1847, the only form known on the Continent was Lept. Liasiana (Bouchard), from the 

 Pic de Saint Loup ; but since then the same shell has been found at May, in Normandy, along with 

 Lept. Bouchardii and L. Davidsoni. 1 Besides the above-named species, Dr. Perier and E. Deslongchamps 

 have also had the good fortune to find in the Lias of Curcy, near Caen, our Leptcena Moorei ; there, as well 

 as at Ilminster, associated with Ter. globulina and Rh. pygmaea. 



Page 18, Leptcena Liasiana, Bouch. 



This species seems to have made its first appearance in the salt marls or Triasic beds of St. Cassian, 

 as may be seen from a series of specimens, forming part of Dr. Klipstein's figured collection, now in the 

 British Museum ; the identity of these examples with the French and British specimens was first suspected 

 by Mr. S. P. Woodward. It is Leptcena (producta) dubia of Muuster, and exhibits the small double area, 

 minute circular foramen, and wide-thickened internal border, common to that species. 



Page 17. 



Leptcena Pearcei must be expunged, as the shell in question would belong, according to Mr. Moore, 

 to the Lamellibranch genus Monotis. At the time of its publication, I had not been able to examine the 

 interior, and the exterior of only one valve and specimen. I feel certain only of the following British 

 species : Lept. Moorei, Dav., L. Bouchardii, Dav., and L. Liasiana, Bouchard. 



Page 26, Spirifer. 



Several minute specimens of Spirifer have been obtained from the Leptcena bed near Ilminster, by 

 Mr. Moore ; the largest measuring from half a line to one and a quarter line in length; and by from one to 

 one and a half line in width. These microscopic Spirifers may perhaps prove to be nothing more than 

 young states of Spirifer Munsteri ; which they approach in shape (but not in dimensions) to that variety 

 named Austriaca by M. Suess. On either side of a comparatively large mesial plait or fold, we find two or 

 three lateral ones only ; but it is well known that, with age, the number of ribs augment in many species. 

 The subject will, however, demand further examination. 



Mr. C. Moore has also lately discovered a small species of Spirifer (Sp. Liasiana, Moore, MS.) in the 

 sands of the infer, oolite, at Dundry. 



1 Refer to M. E. Deslongchamps' 'M£rnoire sur les Genres Leptaena et Thecidea des Terrains 

 Jurassiques du Calvados;' ' Memoires de la Societe Linne'enne de Normandie,' vol. ix, 1853; and to a 

 memoir in the ' Annuaire de 1' Institute des Provinces' for 18.34. 



