346 G. C. Crick—Two Chalk Cephalopods. 
‘possibly also on part ofthe lateral area, by five or six finer ribs, 
which cross the peripheral area in an orad-convex curve; near the 
anterior end of the outer whorl there is, behind each pair of flattened 
tubercles at the edge of the periphery, a similar but smaller pair at 
about two-fifths of the distance between one pair of large tubercles 
and the next succeeding pair; the inner whorl with large. widely- 
spaced obtusely-rounded nodes. 
The holotype (Figs. 1, 2) is a somewhat distorted natural internal 
cast of rather more than | one and a half whorls; the innermost whorls 
are wanting. The fine ribs are specially visible on the peripheral area 
of the first and last portions of the outer whorl, but the surface of the 
specimen is not. sufficiently well preserved to show if these were 
continued over the lateral area. The surface of the fossil generally is 
too imperfectly preserved to show the course of any of the septal 
sutures, although septa appear to have been present throughout fully 
two-thirds of the outer whorl. The specimen, which now forms part 
of the National Collection [B.M. No. C. 12,220], was collected by 
J. R. Farmery, Esq:, after whom the species is named. Its measure- 
ments are: greatest diameter, 91°5 mm. (100) ; width of umbilicus, 
37°5 mm. (41); thickness of outer whorl, 27°5 mm. (80); ‘height of 
outer whorl, 34°75 mm. (38) ; ditto above preceding whorl, 23 5mm, 
(25-6). 
Horizon and Locality.—Turonian, zone of Hotaxtor planus: Boswell, 
near Louth, Lincolnshire. 
A finities and Differences.—The specimen. tool resembles Schliiter’s 
Ammonites auritocostatus,! but that species, recorded by its author 
from the mucronata beds (Senonian) in Hanover, is more narrowly 
umbilicated than the English form; the specimen from near Darup, 
‘Westphalia, which Schliiter® figured and doubtfully referred to this 
species, but has been named “by A. de Grossouvre® Pachydiscus 
ambiguus, and recognized by him in the Middle Campanian at Tauillard 
(Charente), France, is not only more narrowly umbilicated but a 
more compressed shell, the lateral area lacking transyersely-elongated 
nodes, whilst between each pair of nodes ‘at. the margin of the 
periphery there are two or three fairly - prominent simple ribs 
extending uninterruptedly from the umbilical margin over the sides 
and the peripheral area. It is also more widely umbilicated than the 
example from the neighbourhood of Gan, near Pau (Basses-Pyrénées), 
that Seunes* referred to Schliiter’s species, but which Grossouvre? 
1 C. Schliter, pening. cur Kenntniss der jiingsten Ammoneen Norddeutschliands, 
1867, p. 20, pl. i, fig. 2 (Ammonites Proteus, a name preoccupied by d’Orbigny). 
C. Schliiter, “ Qephalopoden der oberen deutschen Kreide,”’ pt. ii: Pal@ontographica, 
Bad. xxi, Lief. ii, 1872, p. 70, pl. xxii, figs. 4, 5 (not 6, 7 = Pachydiscus ambiguus, 
A. de Grossouyre). 
? C. Schliiter, ‘* Cephalopoden der oberen deutschen een pt. ii: Paleonto- 
graphica, Bd. xxi, Lief. ii, 1872, p. 70, pl. xxii, figs. 6, 
3 A. de Grossouvre, Mém. Carte géol. détailide de la Fbhie : Recherches sur la 
craie supérieure. Lop ii: Les Ammonites de la craie supérieure, 1893, p. 198, 
pl. xxix, fig. 3. 
4 J. Seunes, Recherches géologiques sur les terrains secondaires et V éocéne infcrieur 
de la région sous-pyrénéenne du sud-ouest de la France (Basses-Alpes et Landes), 
1890, p. 239, pl. vil, fig. 4 
> A. de Grossouvre, op. cit., p. 197. 
