ON THE kSPINOSE RHYNCHONELLiE 
(Genus AC ANTHOTH IBIS, d’Orbigny), 
found in England, by S. S. Buckman, F.G.S., and John 
Francis Walker, M.A., F.G.S.; read before tbe Yorkshire 
Philosophical Society, December, 1888. 
In this paper we propose to give an account of— 
I. The separation of the genus Acanthothyris from 
Rhynchonella. 
II. The chief literature relating to the Spinose Rhynchon- 
ellce (. Acanthothyris .) 
III. The species and varieties of Acanthothyris which we 
find to occur in England, with their geological and geographical 
distribution. 
Paut I. 
The genus Rhynchonella was founded by Fischer, in 1809, 
(Notice des Foss, du Gouv. de Moscow). His type was 
Rhynchonella loxice from the Oxfordian near Moscow; but for 
some time afterwards these shells were retained in the genus 
Terebratula. 
von Buch, in his classification and description of the Tere¬ 
bratulce fUeber die Terebrateln, 1834, and in Soc. Geol., 
France, Tom 3, 1838 J divides the Terebratulce into Rlicatce 
and Non-plicatas ; while he subdivides his Rlicatce into—I. 
Rlicosce. II. Dichotomce. The last division includes several now 
recognised as genera, namely, Terebratulina , Terebratella , 
Eudesia , Rhychenella pars , Terebrirostra , Uncites , Atrypa , and 
probably several others. Among the species of Dichotomce , 
we find Terebratula spinosa, and Terebratula senticosa. 
Quenstedt (Petrefakten Kunde, 1867,) divides Terebratula 
into—-(I) Terebratulce bicornes. (2) Terebratulce calcispirce . 
(3) Terebratulce annuliferce. (4) Terebratulce loricatce. (5) 
Terebratulce cinctce. (6) Terebratulce impressce. (7) Tere¬ 
bratulce nucleates. (8) Terebratulce biplicatce. (9) Terebratulce 
spiriferince. The first group, T. bicornes , he subdivides into 
Rlicosce RhychonelUclce , in which he places Terebratula spinosa ; 
and into Rentamerus , Uncites and Strigocephalus. 
