NAUTTLID^. 
49 
I append here references to the British fossils which have been 
referred by different authors to Trocliolites pJanorhiformis : — 
1845. Xaidihis primcBvus, Salter, Quart. Journ. Geol. Soc. vol. i. p. 20. 
1852. Trocholites planorhiformis, M‘Coy, British Pal. Foss. fasc. ii. 
p. 324. 
1852. Lituites planorhiformis, Salter, ihid. Appendix A, p. vii. 
1852. Lituites Ilibernicus, Salter, British Assoc. Rep. p. 61. 
1866. Lituites planorhifonnis, Salter, Mem. Geol. Surv. yol. hi. p. 358, 
pi. XXV. f. 5. 
1873. Lituites planorbiformis, Salter, Cat. Cambr. & Shur. Foss. p. 71. 
1882. Nautilus {Trocholites) planorhiformis, Blake, British Foss. Ceph. 
pt. i. p. 213, pi. xxix. ff. 8, 8 «, 9, 9 a. 
Horizon. Trenton Limestone (=Llaudeilo). 
Localities. Montmorenci and Lorette, near Quebec, Canada ; 
MiddleviUe (Herkimer Co.), New York State. 
MTell represented in the Collection. The Canadian specimens 
were presented by Dr. J. J. Bigsby, F.E.S. 
Trocholites Scoticus ?, Blake, sp. 
1882. Nautilus {Trocholites) Scoticus, Blake, British Foss. Ceph. pt. i. 
p. 215, pi. xxviii. f. 4, pi. xxix. f. 6. 
Sp. Char. The following is Professor Blake’s description of the 
type specimen : — “ Rate of increase 1*45. Last whorl *37 ; the outer 
whorls slightly overlapping. The specimen is contorted, and thus 
appears out of symmetry. The section is a nearly uniform ellipse, 
with axes in the ratio of 10 : 9, and the long diameter in the plane 
of curvature. There are no ribs of large size, but the whole is uni- 
formly covered with sharp riblets, which pass obliquely backwards 
and meet at a rounded angle of 60*^ on the front. There are about 
three of these per line in the middle of the whorl. The body- 
chamber leaves the coiled portion for a short distance, and the shell 
is thickened near the aperture, which is parallel to the riblets : thus 
it is oblique, and has a deep concavity on the front, and then the 
shell expands. No septal characters are ascertainable, though septa 
are present.” 
In another specimen Professor Blake found that there were 
22 septa in a whorl. 
Remarks. This species differs from Trochoceras\^^ Lituites^’~\cornu- 
arietis in the absence of annulations. 
The specimen which I have referred to the present species is very 
much crushed, and is altogether in an exceedingly imperfect condi- 
tion, but it has the ornaments described in Blake's species, and is 
PAPvT II. 
E 
