BRITISH AVONIAN CONODONT FAUNAS 221 
DESCRIPTION. The long outer rostral ridge distinguishes this species from S. 
isosticha (Cooper). The ridge is situated on the outer platform and curves away 
from the carina, paralleling the platform margin. It degenerates into a line of low 
isolated nodes before becoming obsolescent near the posterior termination. The 
inner platform bears irregular low nodes over the whole surface. 
Siphonodella sp. A 
Plate 12, figs. 12a, b 
MATERIAL. I specimen : figured, X 537. 
RANGE. North Crop KL 16. 
DESCRIPTION. This specimen is a siphonodellid with a rounded posterior margin, 
and a lobe developed on the posterior part of the outer side. The inner platform 
possesses two longitudinal rostral ridges in its anterior part, the posterior part being 
expanded laterally and ornamented with irregular low nodes, three of which replace 
the carina, while others spread on to the outer platform. The outer platform 
possesses a long rostral ridge, which covers the length of the platform and extends 
along a lobe situated in the posterior part. The platform is unornamented except 
for isolated nodes in the posterior. 
In aboral view the unit is relatively flat and possesses a minute siphonodellid 
cavity. 
REMARKS. This specimen is unlike any other described siphonodellid species. It 
may be a pathologic variant of S. obsoleta Hass. 
Siphonodella sp. 
Plate 31, fig. 20 
MATERIAL. 2 specimens : figured, X 539. 
RanGeE. Avon Gorge K 12-K 17. 
DESCRIPTION. Two fractured specimens of the genus S:phonodella were found in 
the Upper K Zone Beds. One specimen consists of the anterior quarter of the 
platform, and the other of the anterior quarter of the platform and the anterior blade. 
One of the specimens has one rostral ridge and the other two rostral ridges, developed 
on either side of the carina. It is not possible to refer the specimens to any species. 
Genus SPATHOGNATHODUS Branson & Mehl 1941 
1856 Ctenognathus Pander (partim) : 32 (non Ctenognathus Fairmaire 1843). 
1933 Spathodus Branson & Mehl: 41 (non Spathodus Boulenger 1900). 
1940 Pandorina Stauffer 428 (non Pandorina Bory de St. Vincent 1827, nec Scacchi 1833). 
1941 Spathognathodus nom. nov. Branson & Mehl : 98, (pvo Spathodus Branson & Mehl 1933). 
1945 Mehlina Youngquist : 363. 
1957 Ctenognathus (Pandorinellina) Miller & Miller : 1083. 
1959 Pandorinellina Hass 378, (pro Pandorina Stauffer 1940). 
1959 Branmehla Hass 381. 
