BRITISH AVONIAN CONODONT FAUNAS 217 
DERIVATION OF NAME. After Dr. A. Voges. 
Diaenosis. Pseudopolygnathid with triangular platform, widest anteriorly, 
tapering uniformly to pointed posterior. Usually 5 non-marginal bulbous nodes on 
one side of the platform, and six on the other, confined to the margin. Carina 
straight or slightly curved, bearing nodes fused towards anterior and free towards 
posterior. Asymmetrical basal cavity occupying anterior half of platform has fold 
developed on inner side of unit. Blade low and about equal in length to platform. 
MATERIAL. 56 specimens: Holotype X 155, Paratype X 504, X 501, X 505, 
X 507, X 506 (all figured). 
TYPE LOCALITY AND HORIZON. Avon Gorge, lower and middle part of the K Zone. 
Sample K 12. 
Rance. Avon Gorge K 4—-K 14, North Crop KL 1-KL 5. 
DEscrRIPTION. The axis of the unit is straight or slightly curved. The carina 
consists of 12 or more nodes, which are fused at the anterior and free at the posterior 
end. The platform, which is two and a half times as long as its maximum width, is 
widest anteriorly, there being an abrupt taper to the anterior extremity of the 
platform. The margins are slightly convex in the anterior third and taper uniformly 
to the pointed posterior. The posterior tip of the carina continues a short distance 
beyond the posterior extremity of the platform. The outer side of the platform 
extends slightly further to the anterior and is also slightly narrower than the other 
side. It bears up to 5 bulbous nodes, which extend from the margin to the carina ; 
the central node is widest and the anterior two are bigger than the posterior two. 
The inner side of the platform has up to 6 bulbous nodes, which are smaller than 
those of the opposite side of the platform. The anterior four nodes do not extend 
to the carina and are confined to the margin. Asa result, there is an anterior trough 
present in the anterior part of the platform. 
The outer side of the asymmetrical basal cavity is convex and the inner side has a 
fold in the anterior part. The basal cavity is wide and occupies the anterior half of 
the aboral surface. It is pointed posteriorly and rounded anteriorly. The anterior 
blade consists of 5 or 6 denticles which are highest at mid-length. 
REMARKS. P. vogesi occurs in the lower and middle parts of the K Zone in the 
Avon Gorge. It is a homoeomorph of ‘ Pseudopolygnathus dentilineata’ E. R. 
Branson. It resembles P. dentilineatus as illustrated by Voges (1959 : 297, text- 
fig. 5, 11) which is characteristic of the lower part of Cu I in West Germany (Bischoff 
1957, Voges 1959) and Pseudopolygnathus n. sp. of Bouckaert & Ziegler (1965 : 27, 
Pl. 4, fig. 12). In North America, the lowest stratigraphic occurrence of the genus 
Pseudopolygnathus in the Mississippian is the occurrence of P. dentilineatus at the 
base of the Glen Park Formation. P. dentilineatus ranges into the lower and middle 
part of the Hannibal Formation in the Mississippi Valley (Collinson, Scott & Rexroad 
1962). 
Pseudopolygnathus vogesi sp. nov. is similar to P. expansus sp. nov. and transitional 
specimens have been found. 
