On the Senonian Ammonite Fauna of Pondoland. 
121 
which Sharpe * long since had considered to be " better omitted from our 
lists," may be a crushed Pachydiscus of this group. " Pachydiscus " 
vectensis, Sharpe sp., like Sowerby's A. cinctus, apparently is based on a 
malformation. Whether the supposed Turonian Pachydiscus laevicaniculatus 
(Roemer), Lasswitz,f belongs to this restricted Pachydiscus seems doubtful. 
The simple suture-line, with its small external saddle, and the special- 
isation in size mark this genus as a very distinct assemblage of closely 
allied forms. Nowak derived it from Uhligella, but strong costation appears 
repeatedly in Desmoceratidae during the Cretaceous, not only in the 
Aptian, to which formation the true Uhligella is restricted, though probably 
the Pachydiscus ancestor is nearly related to such a Puzosid as that figured 
by Pervinquiere as Pachydiscus sp.{ and quoted by Nowak.§ This stock 
continued into the Senonian, and gave rise, in addition to Kossmaticeras, to 
at least two more developments, resembling the young Pachydiscus peram- 
plus, namely, Nowakites, mentioned below, which attaches itself to such 
forms as ' Puzosia ' le marchandi, Grossouvre,|| of the Lower Senonian, 
and the later Canadoceras, which is a close ally of the Puzosid group here 
separated as Kitchinites. 
Pseudojacobites, gen. nov., 
is here proposed for those Turonian forms that, like P. farmeryi, Crick sp. 
(genotype : " Two Cephalopods from the Chalk of Lincolnshire," Geol. Mag., 
N.S., decade v, vol. vii, 1910, p. 345, pi. xxvii, figs. 1, 2, B.M., No. C 12220), 
develop multituberculation, and attach themselves to the true Pachy- 
discus, possibly via such forms as ' Pachydiscus ' anapadensis, Kossmat sp. 
The exact relations, however, of this latter form, as of 'P.' rotalinus, 
Stoliczka sp., which Kossmat thought might come from the same beds, and 
which is classed as Cenomanian by Nowak, \ are not clear. Boule, Lemoine 
and Thevenin,** and Kilian and Reboul|f record it from the Upper Senonian, 
and the last-named authors put it in the genus Jacobites, but this is a late 
Campanian development of the sparsicosta- giowp of Kossmaticeras ; and 
the inner whorls of ' Pachydiscus ' rotalinus do not suggest affinity with 
* " The Fossil Moll. Chalk of England," II, Cephalopoda, iii, 1857, p. 46. 
f " Kreide Amm. v. Texas," Geol. und Pal. Abh., N.F., vi, 1904, p. 16, pi. iii, fig. 2. 
% " Amm. du Cret. Alger.," Mem. Soc. Geol. France, Pal. xvii, No. 42, 1910, p. 37, 
pi. iii, figs. 1-3. 
§ Loc. cit., p. 347. 
|| "Les Ammon. d. 1. Craie Super.," Mem. Carte Geol. Detail, d. 1. France: II, 
Paleont., 1894, p. 173, pi. xxii, fig. 5. 
% Loc. cit., 1913, p. 347. 
** " Pal. de Madagascar : III, Ceph. Cret. d. Envir. de Diego-Suarez," Ann. de Pal., i, 
fasc. 4 (1906), pi. vi, fig. 5, and pi. vii, fig. 1. 
tt Loc. cit., 1909, pp. 37 and 52. 
