120 BRITISH AVONIAN CONODONT FAUNAS 
Hindeodella cooperi (Elias) 
Plate 31, figs. 18, 19 
1956 Hamulosodina cooperi Elias : 109, Pl. 1, figs. 28, 29. 
Hindeodella cooperi (Elias) ; Collinson & Druce in press. 
MATERIAL. 2 specimens : figured, X 159, X 158. 
Rance. North Crop 3D 14/15. 
DeEscriPTION. The original description of this species is scarcely adequate to 
differentiate it from several others of the genus Hindeodella. The most distinctive 
features of the present specimens, and also of the specimens shown in Elias’ illustra- 
tions, are the greatly elongated posterior bar, the more or less subequal character of 
the denticulation, and the character of the antero-lateral process. The height of the 
denticle is consistent although major denticles can be identified in some parts of the 
bar. The anterior-lateral process is short, vertically depressed, slightly laterally 
deflected, and bears 1 to 4 denticles anterior to the main denticle, with the whole of 
the antero-lateral face undenticulated, and a more or less sharp convex edge. 
In lateral view the aboral surface of the unit is straight to gently concave. Its 
outer face is flat to steeply convex in the anterior part, but becomes more strongly 
convex in the medial and posterior part. The main denticle is not conspicuously 
larger than those which lie behind it. The denticles of the main part of the posterior 
bar are crowded and fused for most of their length, being slightly inclined posteriorly 
and tending to increase slightly in size towards the mid-point of the unit in some 
specimens. In other specimens the main denticle is up to twice as large as the main 
denticles of the posterior series, and in the latter, the hindeodellid character is more 
or less conspicuously developed. The inner lateral face of the unit is flat to gently 
convex. 
The antero-lateral process makes an angle of about 90° with the posterior bar. Its 
postero-aboral edge is straight and points vertically, and makes an antero-aboral 
angle at the anterior edge of about 45°. The denticles anterior to the main denticle 
tend to be about equal in height to those of the major denticles of the posterior bar, 
and curve upwards to lie more or less parallel to the main denticle. The lowermost 
anterior edge of the antero-lateral process is undenticulate. 
The posterior bar is strongly laterally compressed. Beneath the main denticle 
there is a cavity which flares slightly at the edges, and this is extended posteriorly, 
and to a less extent, anteriorly as a narrowing groove. 
Hindeodella corpulenta Branson & Mehl 
Plate 29, figs. 16a-17¢ 
1934 Hindeodella sp. Branson & Mehl: PI. 14, fig. 15. 
1934 Hindeodella corpulenta Branson & Mehl: 281, Pl. 22, figs. 32, 33. 
1934 Metaprioniodus fractus Huddle : 58, Pl. 11, figs. 14, 15. 
1934 Ligonodina conidens Huddle : 63, Pl. 12, figs. 18, 19. 
1938 Ligonodina angulata Branson & Mehl: 142, Pl. 34, fig. 43. 
1939 Ligonodina conidens Huddle ; Cooper : 390, Pl. 45, fig. 45. 
