ACTIXOCEEATIDJE. 
203 
F 
1874. Huronia vei'tebralis, Barrande, Syst. Sil. de la Bolieme, yol. ii. 
Texte iii. p. 746, pL ccxxxi. ff. 6, 7, pi. ccccxxx\d. IF. 5-7 (not pi. 
ccccxxxy. IF. 1-3). 
1875. Huronia vertehralis, Woodward, Manual of tlie MoUusca, 3rd ed* 
n. 192, ff. 56, a, b. 
Fig. 30. 
Huronia vertebrahs.—From a specimen in the British Museum presented by 
Dr. Bigsby. The septa are added from Dr. Bigsby’s drawing ; tliey were 
only indicated in the specimen by “ colourless lines on the brown lime- 
stone.” (After S. P. Woodward^.) 
Sp. Char. The greatest diameter of each siphuncnlar segment is 
to the smallest in the ratio of 13 to 9, and they haye an obliquity 
to the long axis of the shell of about 12°. The inflated rim at the 
top of the segment occupies about one half of the total height. The 
septa arch upwards very abruptly, as seen in Dr. Bigsby’s figure, 
and the rate of tapering of the shell appears to have been rather 
rapid. 
Remarhs. This species differs from H. Bigshyi in the proportions 
of its siphuncle, and consequently in the distance of its septa, the 
latter having been much wider apart in H. Bigshyi than in this one. 
Of the septa nothing but fragments remain in any of the specimens 
in the National Collection, and these are preserved in the narrow 
fissures at the junction of the siphuncnlar elements where they have 
been protected from injury. 
Horizon. Niagara Group (Wenlock). 
Locality. Drummond Island, Lake Huron. 
Bepresented by a large series of specimens, some of which were 
presented by Dr. I. J. Bigsby, F.E.S., and others were transferred 
from the Museum of Practical Geology. 
^ Log. cit. p. 192, f. 56 a. 
