On the Senonian Ammonite Fauna of Pondoland. 
123 
described by the writer from Zululand, and the Parapachydiscus aff. ootaco- 
densis (Stoliczka) described below. P. neubergicus, var. stallauensis, 
Imkeller,* better renamed Parapachydiscus stallauensis, apparently belongs 
to this second division rather than the first. 
Within this comprehensive genus Parapachydiscus several lineages, no 
doubt, could be separated, perhaps by means of the suture-line, but with 
the data available at present such subdivisions appear to the writer to be 
artificial, and he would class as Parapachydiscus, e.g., both Pachy discus holu- 
turensis (Stoliczka), Yabe and Shimizu,f and Parapachydiscus fascicostatum, 
Yabe sp.J 
A bituberculate development, derived from the more globose forms of 
the genus Parapachydiscus, leads to A. menu, Forbes, with scaphitoid 
coiling ; this development is here separated as 
Menuites, gen. nov. 
(genotype : A. menu, Forbes, " Eeport on the Fossil Invertebrata from 
Southern India, collected by Mr. Kaye and Mr. Cunliffe," Trans. Geol. 
Soc, ser. ii, vol. vii, 1845, p. Ill, pi. x, fig. 1, B.M., Geol. Soc. Coll., No. 
10482). M. sturi, Redtenbacher sp., and M. portlocki, Sharpe sp., well 
figured by Griepenkerl § and Wollemann,|| and M . selbiensis, Pervinquiere 
sp., belong to this stock. 
The original figure of Schluter's A. proteus suggests that A. auritocostatus, 
Schliiter, and ' Pachydiscus ' ambiguus, de Grossouvre, represent compressed 
forms of this genus Menuites. 
The possibility of certain Scaphitids of the Campanian (Hoploscaphites, 
Acanthoscaphites ?) having been derived from the present group of Desmo- 
ceratids has already been pointed out by the writer. Other late Senonian 
Scaphitids, however, at present included in these genera, are derived from 
Hoplitoplacenticeras ( = group of ' Hoplites ' vari). 
The Campanian and Maestrichtian genus Parapachydiscus, as here 
understood, is not a direct descendant of the Turonian Pachydiscus. It has 
already been mentioned that in the Lower Senonian there is a group of 
forms, namely, 
* " Die Kreidebild. u. ihre Fauna a. Stallauer Eck u. Enzenauer Kopf bei Tolz," 
Palaeontographica, 48 (1901), p. 57, pi. iii, fig. 5. 
f " Notes on some Cret. Amm. from Japan and California, ' Science Reports, Tohoku 
Imper. Univ., 2nd ser. (Geol.), v, No. 3, 1921, p. 55, pi. viii, fig. 3. 
| " Notes on some Cret. Amm. from Japan and California," Science Reports, Tohoku 
Imper. Univ., 2nd ser. (Geol.), v, No. 3, 1921, p. 57, pi. viii, fig. 5, and pi. ix, figs. 2-5. 
§ " Die Verstein. d. Senon. Kreide v. Konigslutter, etc.," Pal. Abb.., iv, 1889, p. 99, 
(401), pi. xii, fig. 2. 
|| "Fauna d. Liineburger Kreide," Abh. Preuss. Geol. Landesanst., N.F., Heft 37. 
1902, p. 104, pi. vi, figs. 2-3. 
