292 iiE. s. s. BUCKMAX 01s [vol. Ixxiii, 



ticeras,' presumably from Bed 92,^ and is in the cabinet of 

 Mr. James Francis, F.Gr.S., who has kindly consented to its use in 

 illustration. It was communicated to me by Dr. A. Morley Da'V'ies, 

 who had noticed its interest in regard to auriculoids. 



This is not the same species as the last, but it is near, and it 

 illustrates that which there is reason to suppose is the hidden stage 

 of that one. It is earlier — that is 'pve-glevense — biologically, and 

 ma J, for the present, be inscribed as Grleviceras auritulum! glevense. 

 It is earlier because, though exposing three-quarters of the whorl 

 shown by the 3^oung G. glevense, it retains auriculoids all the time, 

 which feature the other had lost about a whorl before. Its ribs 

 are also of a different j^attern, somewhat irregular, connate on the 

 inner area, joined in button -and-loop style on the outer area by the 

 reflected U-shaped auriculoid : a plain rib parts each connected 

 pair. The umbilicus is angulate. Proportions are not much 

 different; but the perijohery is rather blunter. The specimen 

 depicted in PI. XXX, figs. 5 a-oh & PL XXXI, figs. 1 a-1 h, gives : 



S. 22, 44, 29, 26, -K. 



The last of these specimens is much separated by its shape, but 

 becomes of interest now as possessing auriculoids combined with a 

 stout Avhorl and flattened broad periphery. ^ It is Ammonites 

 riparius Oppel,^ from a well at Aston Cross, near Tewkesbmy, 

 presumably from the hiferum horizon. It is thus additionally 

 interesting, as another link between the Gloucestershire and 

 Wiirtemberg faunas.'^' 



Xeither Oppel's figure nor description lead one to expect auri- 

 culoids ; but this example shows them well developed : the}^ are 

 connected too by a longitudinal ridge or pseudo-carina — this is 

 shown by Oppel. The inner margin in the umbilicus is angulate, 

 as noticed for the two preceding specimens : not shown by Oppel. 



This species may presumably be inscribed as Grleviceras ripa- 

 rium (Oppel), for it shows a suture-line (Oppel) — not well 

 exposed in my example (but see PI. XXX, fig. Qd), — which appears 

 to be somewhat more developed than one would expect for this stage 

 of Oxynoticeras\ but there are obviously several steps yet to be 

 distinctively named connecting this species with the last specimen 

 (^G. auritulum I glevense) : they are su23i)lied to a certain extent 

 by Q.uenstedt's figures, pi. xxiv, figs. 15 & 16 in ' Ammoniten d. 

 Schwabischen Jura.' At any rate something ver}^ near to this 

 species may be looked for as common ancestor of Oxynoticeras 

 and Gleviceras, which are thus presumably traceable to a form of 

 Agassiceras pattern but possessing auriculoids, and thus dilfering 

 from that genus. 



For further remarks on auriculoids. Ammonites auritulus, etc., 

 see 'Yorkshire Type Ammonites' A. dennyi 1909, No. 7.] 



^ See Chronological paper. Table V facing p. 267. 

 - Its approximate proportions are : S. 32, 48, 50, 29 4-. 

 =* Pal. Mitth. 1862. pi. x], fig. 2. 

 "* See Chronological paper, p. 270. ■ 



