2 
XArilLOIDEA. 
CA:jj:BKIAy SPECIES. 
Orthoceras serice-um, Salter. 
1866. Orthoceras sericeum, Salter, Mem. Geol. Surv. toI. iii. p. 3oG, 
pi. X. ff. 4, 5. 
1873. Orthoceras sericeum^ Salter, Cambr. & Sil. Foss. p. 18. 
1873. ? Orthoceras, sp., Hicks, Quart. Joiim. Geol. Soc. toI. xxix, 
p. 51, pL iii. f. 27. 
1882. Orthoceras sericeum, Blake, British Foss. Ceph, pt. i. p. 138, 
pi. xiii. ff. 1, 2. 
Char. Owing to slaty cleavage the characters of this species 
are very obscure, all the specimens observed having suffered dis- 
tortion and compression in a high degree. 
The rate of tapering is slow, apparently about 1 in 12, but 
according to Professor Blake ranging in different specimens between 
1 in 8 and 1 in 31. Nothing can be said with certainty about the 
body-chamber. The septa are oblique, remarkably numerous, and 
exhibit a slight curvature ; the angle of their obliquity in the best 
preserved specimen is nearly 45°. About 18 septa are contained in 
the space of 1 inch. 
Salter (Zoc. cz’i.) states that the siphuncle is “ very large, and a 
good deal eccentric, but not quite lateral.” Blake, on the other 
hand, finds it in some examples to be “ central and moderate in 
size, always supposing that the festoon in the septa indicates it.” 
Horizon. Tremadoc. 
Locality. Portmadoc, Caernarvonshire. 
Eepresented by two specimens, Xo. C 611, presented by H. Hicks, 
Esq., M.I)., F.E.S. 
OEDOTICIAX SPECIES. 
Orthoceras Kinnekullense, Foord. 
1887. Orthoceras Kinnekullense, Foord, Ann. & Mag. Xat. Hist. ser. 5, 
vol. XX. p. 401, f. 2. 
Sp. Char. Shell elongate, tapering at the rate of 1 in 9. 
Circular in cross-section. The septa direct, distant about j the 
diameter, strongly arched, their convexity about that of their 
diameter. Siphuncle a little eccentric, about three lines in dia- 
meter where the shell has a diameter of twenty-one lines. Test 
ornamented with regular, direct, flattened, transverse riblets, divided 
by narrow interspaces. Bod^’-chamber unknown. 
