206 
NAUTILOIDEA. 
RemarTcs. The specimen that best represents this species in the 
Collection (Stokes’s type) consists of about seven segments of the 
siphuncle, varying but little in vertical diameter, and thus indicating 
a correspondingly slow increase in the distance of the septa from 
each other. The segment at the smaller extremity has a vertical 
diameter of about six Knes, while the greatest transverse diameter 
is about thirteen. The rate of tapering is slow ; it may be roughly 
estimated at about 1 in 18. About two thirds of the specimen is 
imbedded in the limestone matrix, that part of the segments exposed 
being of a subturbinate form, expanding very rapidly and regularly 
fi’om the base, the diameter of the latter not exceeding 8 lines, 
while that of the expanded portion above measures 13 lines. The 
endosiphon is well seen in the vertical section, fig. 28. All the 
specimens are silicified. 
Horizon. Niagara Group (Wenlock). 
Locality. Drummond Island, Lake Huron. 
Eepresented in the Collection by two specimens figured by Stokes, 
including the type of the species, besides several other examples, 
one of which was presented by the late Sir W. E. Logan, E.E.S. 
Huronia turbinata, Stokes. 
1824. Huronia turhinata, Stokes, Trans. Geol. Soc. ser. 2, vol. i. pt. ii. 
explanation of pi. xxviii. f. 3 ; and p. 203, Species iii. of Bigsby. 
1874. Huronia Rommgeri, Barraude, Syst. Sil. de la Boheme, vol. ii. 
Texte iii. p. 758, and Suppl. 1877, pi. ccccHxiv. ff. 5, 6. 
^ Sp. Char. Bigsby’s description, though brief, expresses the salient 
features of the species, which is only represented by about six seg- 
ments of the siphuncle. It runs thus : — “ In this species, which is 
the smallest I have met with, the column tapers more rapidly, the 
upper part of each joint is more enlarged, and is greater in propor- 
tion to the rest of the joint, than in the two foregoing species ” 
[LT. Bigshyi and H. vertebralis^. 
The rate of tapering cannot be accurately determined, owing to 
the greater part of the specimen being imbedded in the rock, but it 
may be taken at about 1 in 8. 
RemarJes. Barrande has figured a specimen under the name of 
Huronia Romingeri which I am unable to separate from the present 
species. It consists of a fragment composed of two of the segments 
of the siphuncle, one of which only is perfect. This is described by 
Barrande as showing a small longitudinal canal (the endosiphon) 
^ After Dr. Carl Eominger, the State Geologist of Michigan. 
