BRITISH AVONIAN CONODONT FAUNAS 241 
in length. Single accessory lateral denticles are developed in the anterior half on 
each side of the blade. 
The basal cavity is situated slightly posterior to the mid-point of the unit. It is 
very strongly flared laterally and shows a clear tendency to a pseudopolygnathid 
development, but the cavity itself, in spite of its wide flaring lips, tends to be small. 
It extends anteriorly and posteriorly as a shallow groove. The whole unit is gently 
bowed inwards in a horizontal plane. 
Genus TAPHROGNATAUS Branson & Mehl 
1941 Taphrognathus Branson & Mehl: 181 (non Welles 1947). 
Type spEcIES. Taphrognathus varians Branson & Mehl. 
Taphrognathus varians Branson & Mehl 
Plate 13, figs. 4a—5d 
1940 Taphrognathus varians Branson & Mehl: 182, Pl. 6, figs. 27-33, 35-40. 
1944 Taphrognathus varians Branson & Mehl; Branson & Mehl: 246, Pl. 94, figs. 66-68. 
1947 Taphrognathus vavians Branson & Mehl ; Cooper: 92, Pl. 20, figs. 14-16. 
1963 Taphrognathus varians Branson & Mehl ; Rexroad & Collinson : 21, Pl. 1, figs. 18-20, 22. 
1965 Taphrognathus varians Branson & Mehl ; Rexroad & Collinson : 24, Pl. 1, figs. 30-32. 
MATERIAL. II specimens : figured, X 408, X 407. 
Posterior platform 
Anterior blade 
Basal cavity 
LATERAL VIEW 
Anterior blade 
Carina Basal cavity 
| Median 
trough : 
Posterior platform 
carina 
ORAL VIEW ABORAL VIEW 
Fic. 48. Taphvognathus sp. showing morphological terms used in the text. 
