118 BRITISH AVONIAN CONODONT FAUNAS 
DeEscRIPTION. The present specimen is fragmentary but has a very distinctive 
appearance. The posterior bar is elongated and tapers towards the posterior end. 
The main cusp is strongly recurved and strongly laterally compressed in its distal 
half, the proximal half tending to be more rounded. Posterior to it there is a denticle 
adding about a third of the total length of the main cusp, and the denticles posterior 
to this decrease in size posteriorly. They are short, bluntly pointed and discrete. 
The aboral surface of the posterior bar is straight, and the oral surface curves down 
to meet it. The two lateral bars are developed well in front to the line of the main 
cusp, so that the general appearance of the unit in lateral view resembles that of a 
Ligonodina. They are not down-flexed and their aboral margin is in line with that of 
the posterior bar. They make an angle of about 90° with the posterior bar in a 
horizontal plane. They share a single short, but stout, recurved denticle, which lies 
directly anteriorly to the main cusp. 
The aboral surface of the posterior bar is excavated by a wide elongate depression. 
The whole margin tapers towards the posterior end. There is no conspicuous cavity 
below the main cusp. 
REMARKS. One distinctive feature of this specimen is the presence of the denticle 
anterior to the main cusp. This might ultimately justify the recognition of speci- 
mens of this kind as a new genus, but our present material is inadequate to provide a 
full description. Other fragmentary, but different, hassognathids have a much 
greater stratigraphic range. 
Genus HINDEODELLA Ulrich & Bassler 1926 
1925 Hindeodella Bassler : 219 (nom. nud.). 
1926 Hindeodella Ulrich & Bassler : 38-41. 
Type sPEcIES. Hindeodella subtilis Ulrich & Bassler 1926. 
Hindeodella antecomplex Collinson & Druce 
Plate 28, figs. 25, 28 
Hindeodella antecomplex Collinson & Druce in press. 
MATERIAL. 7 specimens : figured, X 157, X 156. 
RANGE. North Crop 3D 4-3D 17. 
DEscRIPTION. The present specimens agree closely with the description given by 
Collinson & Druce. The most striking features of the specimens are their small size, 
the general form of the main denticle, which is relatively massive in relation to the 
general size of the unit, being curved posteriorly and inwardly with a very convex 
interior antero-lateral face. The denticles of the posterior bar range up to about Io 
in number, and the two massive posterior denticles are very prominent in lateral 
view. The denticles show a general increase in size posteriorly, as does the depth of 
the posterior bar. The aboral margin of the posterior bar is straight, and each of its 
aboral lateral surfaces is marked by a flange-like structure. The anterior lateral 
