262 APPENDIX TO THE SUPPLEMENTS TO 



Ventral valve with a slightly convex mesial fold, limited on either side by a feebly marked 

 groove ; beak truncated by a small circular foramen lying close to the umbo of the 

 dorsal valve. Surface smooth, marked only by lines of growth. 

 Length 14, width 12, depth 12 lines. 



Obs. — It seems evident that Terebratula spharoidalis, Sow., T. Sherbornensis, 

 Buckman, T. conglobata, Desk, T. Fileyensis, Walker, T. Eudesi, Oppel, T. globata, Sow., 

 T. Eudesiana, Buckman, and some others, are all closely allied and may be connected by 

 insensible passages in shape, so much so indeed that it is very often difficult to say to 

 which of these so-termed species some of the passage forms should be assigned. T. Sher- 

 bornensis, Mr. S. S. Buckman himself admits to be a form exactly midway or intermediate 

 between T. spharoidalis and T. Eudesi, and it is a question whether we are justified in 

 retaining so many specific names for such closely allied forms. It is true that T. 

 spharoidalis when fully developed is a large, very globose, ball-shaped shell, with usually 

 a straight front line, but in some examples this line is gently curved with a slightly raised 

 rounded elevation or rib bordering a feebly marked mesial depression. 



Leaving out of consideration the intermediate forms and comparing, for example, 

 T. Eudesiana or T. globata with T. spharoidalis, it would be difficult to admit 

 the propriety of merging them into a single species. Perhaps it would be better to 

 retain them as named modifications in shape of, say T. spharoidalis, such as var. 

 Sherbornensis, var. Eudesi, &c. 



Ter. Sherbornensis is a common Inferior-Oolite fossil in the Am. Murchisoni and 

 Am. Sowerbyi beds. Mr. S. S. Buckman stated, when he forwarded the shell to me 

 for description, that he had found it likewise in the Inferior Oolite of Melborne Wick, 

 Somerset, and at Corton Denham in the same county. 



I have added a front view of a typical specimen of T. Eudesi (Appendix, PI. XIX, fig. 

 6) for comparison with a front view of Ter. Sherbornensis, the biplication being deeper 

 and closer in Oppel's than in Buckman's form. 



16. Terebratula Fleischeri ? Oppel. Dav., Jurassic Sup., PI. XVII, figs. 1, 2, 3, 



and Appendix to Sup., Vol. V, PI. XIX, 

 figs. 4, 4 a. 



Terebratula globata, Sow., var., Dav., Jurassic Sup., p. 135, pi. xvii, fig. 1 (2?) 1876. 



— Fleischeri, Oppel. Dav., Jurassic Sup., pi. xvii, fig. 2, 1876. 



— dorsoplana, Waagen. ? S. S. Buckman, Proc. Dorset Nat. Hist. Club, 



p. 14, 1882. 



Shell somewhat subpentagonal, broadest about the middle, as wide as long or slightly 

 longer than wide. Dorsal valve moderately convex, when at about two thirds of its length 

 the valves become biplicated by the formation of two rounded ribs with a concave mesial 



