Annals of the Transvaal Museum 
41 
slightly further forwards than the second lateral saddle. Its most anterior 
portion is very thin and is easily broken. The antisiphonal lobe is very long 
and very narrow. It sends a short secondary lobe outwards and slightly back- 
wards into the upper end cf the dorsal saddle. Further backwards it sends a 
longer secondary lobe with a slightly backward direction into the dorsal 
saddle : further backwards still, it sends another long secondary lobe backwards 
and slightly outwards. This secondary lobe reaches very far backwards. The 
posterior end of the latter is apparently bifid. However, practically only one 
side of the antisiphonal lobe is preserved, and it is apparently not symmetrical. 
Text-fig. 21. Movtoniceras Soutoni. Lobe-line of specimen with broader second lateral 
saddle than that of fig. 19, up to the umbilical suture. Radius 12 cm. Nat. size. 
Text-fig. 22. Mortonicevas Soutoni. Lobe-line of specimen with still broader second 
lateral saddle, up to the umbilical suture. Radius I4’5 cm. Nat. size. 
It is therefore possible that the unknown side may be somewhat differently 
built, although the described side is constant over practically a whole whorl. 
Notwithstanding these differences in the lobe-lines I can see no reason to 
regard these specimens as different species. I have not been so much impressed 
by the differences, that I can regard them as being anything but individual 
peculiarities. This being the case, one has to accept the alternative, that the 
lobe-line may suffer considerable changes in different individuals of the same 
species, and that therefore the comparative constancy of the lobe-line at more 
or less the same age is, at least in some cases, fiction. 
