SUPPLEMENTARY APPENDIX. 29 



In the interior of the ventral valve the dental plates are largely developed, the space between the 

 cardinal muscular impressions being occupied by an elevated mesial septum, to the upper edge of which are 

 fixed two small horizontal triangular plates (in the shape of a shovel). Mr. E. Deslongchamps infers that 

 the place this little group should occupy is one intermediate between Spirifer., Sow., and 

 Spiriferina, D'Orb. 



Note. — The reader is referred to my Memoir on the 'History of the Brachiopoda,' to be published in 

 the ' Transactions of the Linnean Society of Normandy'' {France), vol. x, 1855; also to the same subject 

 printed in the 'Transactions of the Zoological Society of Vienna' (Austria) for 1855. Therein all the 

 improvements suggested to my Introduction will be found fully explained. 



PART III. 



The following new species were discovered by Mr. Moore after my plates had been printed, so that all 

 I can do at present is to add the descriptions communicated by Mr. Moore, and refer for further details, 

 as well as figures, to the fifth volume of the Somerset Archaeological and Natural History Society for 1854. 



Sub-Genus — Zellania, Moore. 



1. Zellania Davidsoni, Moore. 



Shell small, rugose, widest at the front, contracting slightly towards the beak, occasionally presenting 

 a tendency to striation ; large and rounded foramen ; beak slightly produced ; valves convex, the dorsal one 

 but slightly so. Interior presents a rugose structure similar to the exterior of the shell ; dorsal valve has a 

 flattened granulated margin, surrounded by well-defined internal ridges, commencing immediately under the 

 dental sockets. 



Obs. The interior of the dorsal valve and the arrangement of the ridges is not unlike Thecidium 

 rusticum. It is from the Inferior Oolite of Dundry, where it is not uncommon. 



2. Zellania Labouchereii, Moore. 



Shell minute, thin, of an elongated oval shape ; front rounded ; both valves equally convex ; foramen 

 rounded and large, encroaching on both valves ; ventral valve having distinct concentric lines of growth, 

 which in the dorsal valve are not perceptible. 



Obs. The internal organization of this species is unknown. It is readily distinguishable from Z. 

 Davidsoni from its more oval shape and less rugose exterior, and by the lines of growth, which are well 

 defined and constant. 



Locality. Inferior Oolite, Dundry; rare. 



3. Zellania liasiana, Moore. 



Exterior of shell smooth, square ; valves thin and flattened ; ventral one slightly concave, dorsal slightly 

 convex ; foramen large, triangular. Three internal ridges usually showing through the shell give its exterior a 

 plicated appearance. Interior of the dorsal valve shows three strongly defined ridges; the outer, commencing 

 under the dental sockets, slightly curve to the sides of the valve, and are usually lost towards the front of the 

 shell ; the central, commencing at the frontal margin of the shell, generally divides it through its whole 

 length. 



Obs. This species is from the Upper Lias of Ilminster, where it is rare. It differs from the other 

 species by its flattened contour, and by the less symmetrical arrangement of the internal ridges. 



