FROM NORTHWESTERN EUROPE 77 
Internal characters. Pedicle valve. There are no dental lamellae. The deltidial 
plates are disjunct and only weakly developed. The teeth are strong and inserted 
laterally at a rather shallow angle. 
Brachial valve. A cardinal process is not present but the species exhibits the 
thickened inner hinge plates characteristic of the genus. The crura were not well 
preserved but are possibly of the calcarifer type. A median septum is only present 
as a low ridge. 
DISTRIBUTION. The species has only been definitely recorded from the central 
and southern French Jura. 
OccURRENCE. The material collected by Dr. Enay was obtained from dark- 
coloured clays where it was associated with Monticlarella triloboides. 
REMARKS. The specimen sectioned came from St. Sorlin (Jura) one of the locali- 
ties mentioned by Rollier in his original description. 
The separation of A. (Echinirhynchia) lorioli from A. (Acanthorhynchia) spinulosa 
is described under the latter. 
A. (Echinirhynchia) fileyensis (Buckman & Walker) 
(Pl. 7, figs. 4-6) 
1889 Acanthothyris senticosa var. fileyensis Buckman and Walker: p. 56. 
EMENDED DIAGNOSIS. Small to medium sized Echinirhynchia ; beak small and 
suberect to erect ; valves equally biconvex. 
STRATIGRAPHICAL RANGE. Oxfordian—mariae and lower cordatum zones. 
TYPE SPECIMEN. Lectotype, here selected, specimen no. B. 31867 in the Walker 
Collection of the B.M.(N.H.), collected from the Lower Calcareous Grit ot Filey, 
Yorkshire. 
MATERIAL. 6 specimens from the Walker Collection in the B.M.(N.H.) ; nos. 
B. 31313, B. 31335, B. 31275 ; 2 specimens from the collection of the Naturhis- 
torisches Museum, Basel. 
DEscRIPTION. External characters. The shell is biconvex and pyriform in out- 
line with a straight anterior margin. The ribs are fine but well marked and covered 
with spine bases. The beak is small and erect or sub-erect ; beak ridges and inter- 
area are not developed. Details of deltidial plates, if any, and delthyrium not 
observed. 
DIMENSIONS OF FIGURED SPECIMEN. The following measurements are those of 
the lectotype. 
length thickness width 
0-80 cm 0-37 cm 0-74 cm 
Internal characters. Not investigated through lack of material. 
DISTRIBUTION AND OCCURRENCE. The species has only been definitely recorded 
from Filey, Yorkshire, where it occurs in the Lower Calcareous Grit. The only other 
possible conspecific material known to the author is two specimens from the 
“ Renggeri-Thon ”’ of Baden, in the collection of the Naturhistorisches Museum, 
Basel and numbered L 1701/1-2. 
