16 
DESCRIPTIONS OF TWO COMPARABLE ENGLISH SPECIES 
A form comparable with Paracephalites jucundus occurs in the Kella- 
ways Rock of South Cave, South Yorkshire. It is at first sight so much 
alike that a short description of it with figures may be of interest. 
Genus, catacephautes S. Buckman 
1922. Catacephalites S. Buckman, Type Ammonites, IV, legend of Plate 
CCLXXXIIL 
Genotype, C. durus S. Buckman, holotype 
Sphaerocone of Macrocephalitoid aspect, also very like Otoites con- 
tractus J. de C. Sowerby (S. Buckman, PL CLVIII) except for a lack of 
tuberculation and difference of suture-line. Ribs flexicostate, passing 
straight over venter. Suture- line like that of Paracephalites but more 
simple. 
There is no external difference from Paracephalites and if it were not 
for the suture-line it could be placed in that genus. But the suture-line is 
different— EL lacks entirely the accessory branch passing into ES which is 
so well developed in Paracephalites . LI is simpler with very feeble develop- 
ment of the tridactyloid character, L2 is fairly long. 
Catacephalites durus S. Buckman 
(Plate III, figures 12, 13) 
1922. Catacephalites durus S. Buckman, Type Ammonites, IV, Pl. 
CCLXXXIIL 
Holotype from South Cave, South Yorkshire; Kellaways Rock; Mr. 
Frank Fetch, Coll. 
Proportions: S. 33, 45, 72, — 
S. 44, 45 • 5, 65, 22 
Size of specimen 51 mm., maximum size c. 55 mm. 
Owing to the condition of the specimen the proportions must be con- 
sidered approximate. 
Proportions of suture-line to whorl-breadth of 15 mm. 
EL 73, LI 63, L2 37 per cent 
Proportions of suture-line to whorl-curve of 27 mm. 
EL 41, LI 35, L2 20*5 per cent 
Sphaerocone, flexicostate. Primary ribs curve forward over umbilical 
wail and bifurcate beyond it into about radial secondaries, which pass 
straight over a well-rounded periphery. 
The likeness of Catacephalites durus to Paracephalites jucundus sug- 
gests that it is the European equivalent of the Canadian species. 
To Ammonites (Macrocephalites) ishmae var. arcticus Newton (PI. 
XL, fig. 1) C. durus has considerable likeness; but the primary ribs of the 
English fossil are stronger, with more curvature, the secondary ribs are 
rather more approximate on the venter, the thickness of the conch is 
greater, the umbilicus is larger. Proportions of Newton’s shell are F. 
