34 Annals of the Transvaal Museum 
Nothing is preserved of any possible finer ornamentation of the shell. The 
undulations of the flank seem to be of the same type as those of P. umzamhien- 
sis; however, this species has also very prominent undulations immediately 
around the umbihcus. 
The lobe-line greatly resembles that of P. umzamhiensis. There is, however, 
some difference in the detail. The external lobe is probably similar to that of 
P. umzamhiensis. The anterior secondary lobe of the external lobe is plainly 
visible as also a portion of the posterior one. The first lateral lobe, which is 
short and of moderate breadth, is much shorter than the external lobe, its 
length being about two-thirds that of the last. Its posterior end reaches just 
as far backwards as the anterior secondary lobe of the external lobe. The 
second lateral lobe is long and moderately broad. It is only slightly shorter 
than the external lobe, which, however, reaches much further backwards. The 
secondary saddles and lobes along its outline are of irregular length and 
breadth; there seems to be a tendency to bifidity. The third lateral lobe is 
short and broad. It is much shorter than the second lateral lobe and reaches 
about half as far backwards as the external lobe. There are many secondary 
lobes and saddles along its outline. The fourth lateral lobe is shorter and 
narrower than the third; it reaches slightly further backwards. The outer 
portion of its outline is modified by some small secondary lobes and saddles. 
From the fourth lateral lobe inwards there is a series of five small lobes, with 
a possible sixth on the umbihcal edge. These lobes are more or less of the same 
length and breadth, the outer ones being slightly longer and broader than the 
inner ones, as far as visible. Counting from outwards, the third and fourth of 
these lobes may also be taken as one lobe with a large secondary saddle 
dividing it. 
The three first lateral saddles are broad. The two first have a generally 
rounded anterior contour, while the third is rather broad and flattened 
anteriorly. The second saddle already shows a bifid arrangement, and the 
third is clearly bifid, while both its arms are also bifid. The fourth lateral 
saddle is much narrower than the third; it is bifid. The five small saddles 
inwards from the fourth are subequal. The outer ones are slightly longer and 
broader than the inner ones. 
Measurements: the diameter of the last whorl cannot be obtained. The 
vector of the last whorl, where the sutures have been made visible, has prob- 
ably a length of 54 mm. The thickness of the shell at this place is about 22 mm. 
This species differs from the type especially in the blunt keel (of the later 
stage?) and the prominent undulations around the umbilicus. There is also 
difference in the lobe-line. The portion internal to the fourth lateral saddle in 
P. amapondensis is long and consists of five small saddles. In P. umzamhiensis 
this portion is short and occupied by only one fairly large saddle. The fourth 
lateral saddle in P. umzamhiensis is much broader than that in P. amapondensis. 
Further differences in the lobe-line may be gathered from the figures. The 
lobe- line shows differences with that of Pelecodiscus Jullieni Pervinquiere sp. 
also. This will best be seen by comparison of the figures. The undulations of 
the shell near the umbilicus seem to be broader in our form than in the 
Algerian one. 
This species is based on only one fragmentary specimen. 
