ACTIXOCERATID^. 
201 
RemarTcs. I cannot pass by without comment the views of such a 
competent authority as Billings, upon the affinities of Huvonia h 
He denied that the characters relied upon to separate Huronia hom 
Orthoceras had any generic or even specific value, because he ob- 
served specimens in the Collection of the Geological Survey of 
Canada, which exhibited, as he conceived, “both turbinate and 
nummuloidal joints in the same individual.” ISTow I think there 
can be no doubt that Billings encountered the same struotui’e as 
that which is illustrated in fig. 28, but he failed to recognize that 
the two forms (the turbinate and the nummuloidal) do not exist 
apart, i. e. in different individual segments, but are combined in one 
and the same segment, as I have already described. The mistake 
probably arose from the study of specimens in which the dual 
character of the segments was not clearly shown. 
Huronia was first described by Stokes (loc. cit.) as a Coral, and in 
this view of its affinities Dr. Bigsby shared; but upon further exami- 
nation and comparison this impression was removed, when it was 
found how closely Huronia agreed in structure with Actinoceras. 
AVe learn from Dr. S. P. lYoodward (Joe. cit. p. 192) that out of 
the numerous examples of Huronia collected on Drummond Island, 
only two showed any trace of septa or shell ; the rest consisting of 
the siphuncle only. He adds that “ some of those seen by Dr. 
Bigsby in the limestone cliffs were 0 feet in length.” 
Huronia had a comparatively brief duration in geological time, 
having been confined, so far as is known, to the ISliagara epoch of 
the Silurian. It was limited in geographical range to the rocks of 
the Niagara Group in North America. 
Huronia Bigsbyi, Stokes. 
1824. Huronia Bigshyi, Stokes, Trans. Geol. Soc. ser. 2, vol. i. pt. ii. 
“ Explanation of Plates,” pi. xxviii. f. 1 ; and p. 203, Species ii. 
of Bigsby. 
1851. Huronia annulata, Hall, in Rep. on the Geol. of the Lake 
Superior Land District, by Foster and Whitney, pt. ii. p. 221, 
pi. xxxiv. f 4. 
1870. Huronia Bigshyi, Barrande, Syst. Sil. de la Boheme, vol. ii. 
Texte iii. 1874, pp. 743, 757, pi. ccccxxxvi. ff. 1-3. 
1877. Huronia Bigsbyi, Barrande, ibid. vol. ii. Supplem. et Ser. 
tardive, pi. cccclxxiv. ff. 2-4. 
Char. The only characters available for distinguishing the 
species of Huronia (except perhaps in one instance) are those which 
' Geol. Surv. of Canada, Eep. of Progress, 1853-56, p. 323 et seq. 
