24 The American Geologist. January, 1905 
that in these fossils and in those from lake Nipissing, the 
subsequent and prolonged portion of the siphuncle is quite 
different from that of the western J^. aulema. 
The same museum now contains a collection of speci- 
mens of siphuncles of at least four species of Endoceratidae 
with the apical end preserved, from the Cambro-Silurian 
rocks at various localities in Ontario and Quebec. A few of 
these specimens are silicified siphuncles, that are either 
water-worn or that have been treated with acid, but by far 
the greater number are mere casts of the interior of the 
siphuncle. The silicified specimens show the general shape 
of the siphuncle, and the casts the same, with the addition of 
more or less well defined, obliquely transverse annulations 
or "septal rings," and most of the structure of the interior. 
In three of these specimens, the apical end of the siphun- 
cle is not gibbous, or abruptly swollen and then suddenly 
contracted, on the convex inner side, as in Nanno, and theri 
generic position is uncertain. Two of them are from the 
Black River hmestone at Paquettes rapids, and the other is 
from the Lorraine shales at the Don brick yard, near 
Toronto. 
The two from Paquettes rapids, which are very different 
from those from that locality that had previously been re- 
ferred to Nanuo aulema, are silicified and badly preserved. 
They are both acutely pointed posteriorly, and the apex of 
each is eccentric, as represented by figure i, on plate II. In 
external form they are not at all unlike the pointed end of 
the guard of a rather slender belemnite. They are, also, 
very similar in shape to the anterior endocone of the siphun- 
cle of a Vaginoceras, like that of V. commune, as figured on 
page 514, fig. 1055 B, of Eastman's translation of Zittel's 
Text Book of Palaeontology. But, externally, they both 
show distinct traces of obliquely transverse annulations or 
septal rings over the greater portion of their surface, and, 
internally, there is a deep, funnel-shaped cavity, or endocone, 
at the imperfect anterior termination of each. 
The specimen from the Don brick yard, which is repre- 
sented, a little reduced in size, by figures 2 and 2 a on plate 
