Annals of the Transvaal Museum 
147 
lobe lies external to the umbilical margin. It is very short and its posterior end 
lies far in advance of the posterior end of the second lateral lobe. On the 
umbilical surface the lobe-line runs as far backwards as the posterior end of 
the second lateral lobe. 
approximately about 
about 
44 mm 
17 „ 
12 ,, 
8 ,, 
8*5 mm 
13-5 „ 
(1) 
(o-39) 
(0-27) 
(0*18) 
(0-19) 
(o-3i) 
Measurements : 
Diameter 
Height of last whorl 
Thickness of last whorl 
Height of penultimate whorl 
Thickness of penultimate whorl 
Diameter of umbilicus 
This is another form belonging to the group of Holcodiscus Aemilianus 
Stol. sp. It differs from H. Kandi Stol. sp. by having the ribs flattened on 
the periphery and by the fact that all the ribs start at the umbilicus. The 
constrictions have also a different shape. In H. madrasinus Stol. sp. the ribs 
pass with undiminished strength across the periphery, while the constrictions 
are more numerous and cut off more ribs. There is great resemblance between 
our form and H. karapadensis Kossmat. In the Indian ammonite, however, 
the ribs are not conspicuous on the inner portion of the flank and the sulci 
are directed more forwards, so that more ribs are cut off. The shape of the 
sulci is also different. The height of the whorl augments quicker in our form 
than in H. karapadensis. In H. buddhaicus the whorls are broader than high. 
One side of the last whorl shows a portion of the last mouth edge. If this 
edge is identified correctly, the body-chamber occupied slightly more than 
half a whorl. 
