286 ME. s. s. BTJCKMA?^ o:s [vol. Ixxiii, 



History of figured specimens. — The holotype is from the 

 collection of Mr. D. S. Darell, F.L.S., F.Gr.S., and was obtained 

 from South Petherton (Somerset), evidently by its matrix from 

 Marlstone or associated beds. The other two specimens were pur- 

 chased b}^ Mr. J. G. Hamling, F.Gr.S., at the sale of the effects 

 of the late E,ev. Ingle Dredge : they were in a drawer labelled 

 ' Middle Lias, Grretton.' The piece of matrix which yielded the 

 larger specimen was preserved too — a very good practice : it is a 

 bluish calcareous stone of Marlstone character, and Grretton near 

 Winchcomb (Gloucestershire) was a well-known Marlstone locality. 

 See later, p. 308. I desire to express my thanks to Mr. Hamling 

 for kind presentation of these specimens. 



Table XII. — Proportions : Leptaleocjesas and like Forms. 



L. Upturn, yo^xllg shea S. 25, 34, #19, 40. 



r24, 33, 18, 41. 



L. Upturn, holoty-pe'^ S.^ 35-5, 30, 17, 43. 



[66, 24, 16, 52. 



L.Si&.Uptum S.35-5, 34, 20, 39. 



Ammonites normanianus'D''Ovhignj" T. 90, 31, 17, 45. 

 Protogrammoceras cornacaldense, 



Y&r. zeugita7ium, Spsith.,lii, la^. . T. 60, 30, 18, 46. 



Am.pseudoradians^ejJ).es,i[bis'],4<'^ F.46, 37, 21, 37. 



Am.fieldinginejnes,iY,la,b*... F. 24, 33, 24, 47. 

 Harpoceras domeriense Meneghini, 



App. i,|55 F.31-5 30, 26, 48. 



Family POLYMORPHID.E. 



AcAiN^THOPLEUEOCEEAS EUESicosTA, nom. nov. (PI. XXVI, 

 figs. 4 a-4c.) 



1884. Ammonites valdani Quenstedt (no)i D"Orbigny), ' Ammoiiiten d, Schwab- 

 isclien Jura" pi. xx.w, Hg. 4 oul}'. 



Proportions.— S. 1260, 28, 20. 48. 

 \190, 32, 22, — . 



Description. — The featm-es of the type are its large size and 

 the i'eclination of the ribbing. The general features are well shown 

 in Quenstedt' s cited figure — the reclination is less ; but increase of 

 reclination may be due to age, to which also is to be attributed loss 

 of inner roAv of tubercles, rounding of periphery, and decay of keel. 

 The proportions of Quenstedt's fragment I estimate at F. 112, 30, 

 20, 48. 



Distinction. — Reclination of ribs, presence of many marked 

 subsidiary costulse on periphery, less size of tubercles, convexity 

 instead of concavity of intertuberculate lateral area distinguish 



^ The specimen being broken, approximate measures of inner whorls can be 

 given. 



2 ' Pal. fran^. : Terr. Jur. Ceph.' 1844, pi. Ixxxviii & p. 291. 



^ Op. jam cit. "^ ' Geol. Pal. Aveyron.' 1868. 



^ ' Lias sup.' in Stoppani's Pal. Lomb. (4) 1881. 



