290 ME, s. s. Bi'CEMAi^ ON [vol. Ixxiii, 



Remarks. — These details are drawn up from the holotype. The 

 paratype, Ammonites greenhoitghii of the ' Geol. Chelt.,' agrees so 

 closely with Wright's cited figures of Amaltlietis guihalianus and 

 his description of that form (p. 386), that there need be added 

 only these remarks : — The periphery in Wright's figure is sharper, 

 possibl}^ due to presence of test, the ribs are stronger — over- 

 accentuation of such a character is quite usual in drawings, — and 

 the inner edge of the penultimate whorl is more exposed : the 

 paratype, and the holotype too, show a particular! 3^ concentric 

 coiling of the umbilicus, which may be called thimble -shaped, 

 indicating that in the young the species must be rather thin and 

 somewhat widely umbilicate. 



The paratype shows (PI. XXVIII, fig. 2) a rather narrow- 

 stemmed superior lateral lobe, with a fairly even arrangement of 

 fine lobules towards the end : the broader- stemmed lobe of the 

 holotype is presumed to be due to old age. 



Below are given the proportions of certain comparable species 

 with those of the species now described. The first three differ in 

 proportions, especially in the greater umbilication ; Reynes's 

 Ammonites guibali is difficult to place in the series, as no informa- 

 tion is given of thickness nor whether it is a large shell reduced. 



The very longstanding and Yurj general confusion of Oxynotoids 

 of the Gleviceras pattern with Ammonites greenouglii J. Sowerby 

 has now been exposed and corrected in a \qyj careful paper by 

 Mr. Spath.^ But the likeness when, in large sj^ecimens of the 

 present species, ribs are lost and the keel is obsolescent or obsolete 

 is certainh^ remarkable. 



History of specimens. — The holotype is from Lias clays 

 above the oxynotum horizon, from the lower part of Folly Lane 

 Brickyard, Cheltenham (Grloucestershire). The paratj^pe was re- 

 corded as Ammonites greenhoitghii from Lias shales, Lansdown, 

 Cheltenham, Coll. J. Buckman (' Greol. Chelt.' p. 89). 



Table XIV. — Proportions : Gleviceras and like Forms. 



^m. cZoHsEeynes,xli, 13-152 ... F. 109, 48, 32, 22. 



Am. aballoensis Dvim. 11, xxxviii." F. 117, 48, 35, 20. 



^m. ^reenon^/ii Hauer, xii, 2, 3, 4.^^ F. 112, 48, 29, 20. 



^m. ^wi&aU Eeynes, xlvi, 13 2 ... F. 203, 47, — , 20. 



r 86, 47, 25, 19. 



Gleviceras glevense, h.olotj-gQ S.^ 128, 51, 26, 14. 



[184, 51, 27, 14. 



Cr. i/leren-se, paratype S. 148, 52, 26, 14-5. 



{Atyi. greenJioughii J. Buckman.) 

 G. glevense. 



{Amaltheus guihalianus Wright, (F. 157, 54, 26, 14. 



xlv, 67, p. 386)= ^T.133, 56, 26, 15. 



^ ' ScMotheimia GreenougJii ' Geol. Mag. dec. 6, vol. ii (1915) p. 97. ■ 



- ' Mon. Amm.' 1879. ^ ' Bassin Rhone.' 



■* ' Ceph. N.O.-Alpen ' Denkschr. k. Akad. Wissensch.. Wien, vol. xi, 1856. 

 ■ ^ ' MonogT. Lias Ammonites' (Pal. Soc.) 1881. 



