218 SUPPLEMENT TO THE BRITISH 



224. Rhynchonella (?) coronata, Moore. Sup., PI. XXVII, fig. 13. 



Rhynchonella (?) coronata, Moore. The Geologist, vol. ii, p. 191, pi. ii, figs. 23 — 



25, 1861. 



Both this and the preceding fossil have all the appearance of being the fry of some 

 species not at present determined. The character of the beak would evidently lead to 

 this conclusion ; and, indeed, I might also express the same suggestion with respect to the 

 minute shells described by Mr. C. Moore under the designations of Spiriferina minima 

 and Sp. Oolitica. M. E. Deslongchamps even questions the value of the genus 

 Zettania, and is under the impression that all the species referred to it are the fry of some 

 other species, of which full-grown specimens occur in the same rocks. This is, however, 

 a question requiring further investigation, and therefore it will be preferable, provisionally 

 at any rate, to retain Mr. C. Moore's genus and species. Mr. C. Moore describes his 

 Rh. coronata in the following words : 



" Shell small, smooth, rounded ; ventral valve rather convex ; dorsal valve more 

 flattened, and with a slight sinus ; beak produced, with a large triangular deltidium, 

 bordered by a narrow area, from which spring two raised, lateral, ear-like processes, which 

 again fold over upon the area. Under the above the valve possesses strongly marked hinge- 

 beak. The shell is from the Upper Lias of Ilminster, whence I have nine examples. The 

 lateral ear-like expansions give it a very peculiar appearance. With some little doubt it 

 is referred to the genus Rhynchonella, though the shell-structure appears to agree most 

 with that genus." 



Obs. — This shell was badly drawn in the ' Geologist ;' there exists a narrow depres- 

 sion all along the middle of the dorsal valve, as will be seen in the more correct drawings 

 I have made from Mr. Moore's specimens. His figures are likewise too square. Prof. 

 Tate quotes it from the zone of Am. jurensis. 



225. Rhynchonella Tatei, Dav. Sup., PI. XXVIII, fig. 45. 



Shell small, transversely oval, or wider than long. Dorsal valve more convex and 

 deeper than the ventral one, and divided into three lobes of about equal breadth, the 

 central one forming a wide, slightly raised mesial fold. Ventral valve with a broad, 

 shallow sinus ; beak pointed, incurved ; foramen minute, and separated from the hinge- 

 line by its small deltidial plates ; surface of both valves ornamented by about eighteen 

 small ribs, of which about six occupy the mesial fold. 

 Length 4^, breadth 5, depth 3| lines. 



