332 
Transactions of the Royal Society of South Africa. 
Sub-family PACHYDISCINAE. 
Genus Parapachydiscus, Hyatt. 
17. Parapachydiscus aff. ootacodensis, Stoliczka sp. 
(Plate VII, fig. 6.) 
1921. Parapachydiscus sp. ind., Spath, loc. cit. (Pondoland), table to 
p. 50. 
In the description of Parapachydiscus sp. n. aff. colligatus, Binkhorst sp., 
from Zululand, the writer referred to two large specimens in the present 
collection, not described by Crick, that " may belong to Parapachydiscus of 
the colligatus- supremus type." One was described as having " an umbilicus 
of 19 per cent, and a thickness of 45 per cent, of the diameter," the other as 
showing " at a whorl-height of 260 mm. a thickness of 200 mm." Both 
were stated to be more compressed than the Zululand example described, 
and to be intermediate in sectional outline between fig. 30 (P. colligatus) 
and fig. 31 (P. oldhami) in Nowak.* 
The larger fragment (C 19439) is described above as Parapuzosia haugh- 
toni, sp. n., since development of its dorsal area has shown that the resem- 
blance of its smooth outer whorl to the Parapachydiscus here described was 
only superficial. The smaller example (No. C 19438), also labelled " Pachy- 
discus sp." by Crick and not described, has the following dimensions : 
at diameter = 150 mm., -50, -45, -19. 
At the diameter of 59 mm. the whorl-height = 29 mm., and the thickness 
= 31 mm. ; on the other hand, where the height of the outer whorl = 150 
mm., the thickness is only 125 mm., so that whereas, at first, the whorl- 
section is round or slightly depressed, with increase of size it becomes com- 
pressed. The specimen is still septate at this stage. 
P. ootacodensis shows a similar change of proportions, with age, i.e. 
from the more inflated inner whorls (Stoliczka's fig. 4 of pi. liv) to the more 
compressed adult figured by Stoliczka on pi. lvi. The ribbing also is 
similar, though the inner whorls seem more distinctly costate in the Pondo- 
land form, almost as strongly ornamented as those of the much more inflated 
P. sp. n. aff. colligatus, figured by the writer. The present form is thus 
transitional to the more coarsely ornamented P. grossouvrei (Kossmat) = 
A. ootacodensis, Stoliczka, pi. lvii, non caet., but none of the ribs reaches 
to the umbilical border. The umbilical edge is perhaps not quite so marked 
as it is in Kossmat's smooth Indian example. f 
The suture-line differs from that of P. ootacodensis in having the four 
* Loc. cit. (1913), pi. xliii. 
t Loc. cit. (1898), fig. 16, pi. xvi (xxii). 
