ACTIXOCEEATID^. 
185 
Stokes gives us no description whatever of this species, but refers 
the reader to Bigsby’s figure, and observes that the species was 
“ named after M. White, Esq., of the Army Medical Staff, who was 
stationed on Drummond Island, and collected this and many other 
specimens of these interesting fossils.” 
Honzon. Magara Group (Wenlock). 
Locality. Drummond Island, Lake Huron. 
Eepresented in the Collection by the type specimen figured by 
Bigsby. 
Actinoceras vertebratum. Hall, sp. 
1840. Ormoceras Bayfieldi, Stokes, Trans. Geol. Soc. ser. 2, vol. v. 
pt. 3, p. 709, pi. lx. f. 1. 
1852. Ormoceras vertebratum^ Hall, Pal. of New York, vol. ii. p. 94, 
pi xix. ff. 1, a-y. 
1852. Ormoceras Bayfieldi, Giebel, Fauna der Vorwelt, Band iii. 
Abth. i. p. 204. 
1855. Ormoceras Bayfieldi, Barrande, BuU. Soc. Geol. de France, 
s4r. 2, tom. xii. p. 470, pi. A. f. 5. 
I860. Orihoceras {Ormoceras) Bayfieldi, Barrande, Syst. Sil. de la 
Boheme, vol. ii. Texte iii. 1874, p. 738, pi. ccxxxi. f. 1. 
Bp. Char. “ Shell elongated, gradually tapering, section circular ; 
siphuncle nearly central (?) ; surface unknown ; septa four to five in 
the space of an inch; edges of the sepia slightly projecting in the 
cast, and the spaces between them contracted or concave ; siphuncle 
presenting the usual appearance of Ormoceras, the longitudinal 
diameter of the expanded portions being about one-half as great 
as the transverse diameter. . . . Many of the specimens are 
weathered, exhibiting the structure in a very beautiful manner, and 
showing also the variable aspects under which the same species may 
be presented.” {Hall.) 
Reinarhs. I entertain no doubt whatever as to the identity of 
Stokes’s species with Hall’s ; and as we must depend upon the last- 
named author for an adequate description of the species, it is but 
just that his name should supersede that of Stokes. The diagnosis 
given by the latter is in the following words : — “ Shell slightly 
conical. The laminae of the septa separate from each other on one 
side of the shell so as to show a space between them.” This latter 
character, which cannot, however, be regarded as of specific import- 
ance, is noted also by Hall, who describes one of the specimens 
figured by him (f. 1 c) as having the laminae of the shell silicified 
and separated, “ so that the septa and siphuncle appear to be com- 
posed of double laminae,” just as in Stokes’s specimen. 
