128 BRITISH AVONIAN CONODONT FAUNAS 
Hindeodella sp. nov. 
Plate 28, figs. 14a, b 
MATERIAL. I specimen: X 186 (figured). 
TYPE LOCALITY AND HORIZON. North Crop. Sample 3D 14/15. 
DescrIPTION. A single specimen is tentatively regarded as a new species of 
Hindeodella, although it may be a pathologic form. It is characterized by a con- 
tinuously recurved, hooked anterior lateral process and a very sinuous posterior bar. 
The general appearance of the unit is of a question mark, with the posterior end 
forming the base of the question mark. The posterior bar is shallow, being about 
equal in depth to the smaller series of denticles developed on its oral surface. Its 
aboral edge is strongly convex in its anterior half and concave in its posterior half, so 
that the whole effect is of a sinuous development. Its outer lateral face is strongly 
convex in the anterior half, and flat to gently convex in the posterior part. 
The oral surface of the posterior bar bears a series of about 18 denticles of variable 
size, which show no regular alternation. They are basally confluent but apically 
distinct, and are sharply pointed, with sharp anterior and posterior edges. Those 
near the posterior end tend to be more strongly inclined posteriorly than those in the 
anterior part, which are only gently inclined posteriorly. Although these denticles 
show no regular alternating arrangement, some of them are conspicuously larger than 
others and these are developed at variable intervals. The largest of them are about 
twice the length of the smallest, and they show a broad tendency to increase in size 
posteriorly. Their total number is probably greater than 18 as the present specimen 
is broken. The main denticle is about equal in size to the largest denticles of the 
posterior bar, being sharply recurved and incurved. Immediately posterior to it the 
aboral surface of the posterior bar is flat, although its general structure is still broadly 
convex. 
The antero-lateral process consists of two more or less distinct parts. There is a 
sharply up-flexed part, in which the aboral edge of the process makes an angle of 
about 70° with the aboral edge of the posterior bar immediately posterior to the main 
denticle. It is not greatly flexed to the natural plane, however. On the anterior end 
of this are two conspicuous denticles, which are incurved, as well as recurved, so that 
their ‘‘ anterior and posterior ”’ edges are in fact lateral in position. They are greater 
in size than the main denticle and exceed the size of the largest denticles of the 
posterior bar by about a half. The aboral surface of the unit is excavated by a very 
thin groove. 
Genus HINDEODUS Rexroad & Furnish 1964 
1964 Hindeodus Rexroad & Furnish : 671 
Type spEcIES. Tvichonodella imperfecta Rexroad. 
