26 The American Geologist. January, 1905. 
specific determination or description, but such apparently 
valid genera as Huronia, Discosorus, Deiroccras and Narthe- 
coceras have, nevertheless, been practically based upon just 
such specimens. Incidentally, also, it may be mentioned 
that the flattened outer side of the siphuncle in Endoceras 
marcoui, E. beletnnitiforme, and Nanno aulerna, upon which 
the obliquely transverse annulations are arched forward, is 
called the dorsal side by Barrande and Clarke, the peripheral 
by Holm, and the ventral by Hyatt. In this paper it will be 
called indifferently the peripheral, outer, or flattened side. 
These siphuncles group themselves naturally into at 
least two species, both of which are apparently undescribed, 
though it is by no means certain that both belong to the 
same genus. One of these species is represented by a single 
specimen. from the Calciferous of Ontario, and the other by 
several specimens from Kingston Mills, also, possibly, by 
all those siphuncles from lake Nipissing and Paquettes rapids 
that had previously been identified with Nanno aulema. 
These two species may be provisionally named and charac- 
terized as follows : 
NANNO PRIMAEVUS, sp. nov. 
PLATE n— Figs. 3 and 3 a. 
Apical cone of the siphuncle, the only part known, al- 
most straight on the flattened peripheral side, slightly swollen 
at a short distance from the apex on the opposite or convex 
side, then lightly or shallowly contracted on that side, and 
ultimately increasing very slowly in thickness, the commence- 
ment of the prolonged or longicone portion being nearly cir- 
cular in transverse section, but also flattened on the peri- 
pheral side. 
Surface of the apical portion of the endocone smooth; 
its anterior and contracted portion rather obliquely, and 
closely but faintly annulated, though the annulations, or ob- 
scure low annular ridges, appear to be interrupted on the 
smooth and flattened peripheral side. These annular ridges 
are numerous and close set, though they are unequal in size 
and irregular in their distances apart. 
