S14 



Or.TIIOCEP.AS ISIlPSIFQUOI. (N. sp.) 



Fig. 303. 

 Fig. 303. — Siplmncle of 0. Missisquoi, tlie most common form. 



De^^eription. — No specimens of this species -widi the septa preserved 

 have been found, but the siphuncle, represented by the al)Ove figure, 

 occurs in great numbers in one locality, in B 2, at Phillipsburg,. The 

 must common form (of the sipliunclc) is three or four inches in length, 

 gently curved,, tapering at the rate of about one line and one-third to the 

 inch, and marked by from nine to twelve septal rings to the inch. As 

 those rings are most distant from the apex on the concave side, it is 

 evident that the position of the siphuncle, in the fossil, is near the shell 

 on the dorsal side, or on the side of the concave curve. 



Associated with this short curved form, there are numerous others, 

 more elongated, somewhat straighter, and not quite so rapidly tapering. 

 The septal rings are sometimes more rounded, or more like the annulations 

 on such shells as 0. arciwUratiun. Similar differences are exhibited by 

 the detached siphuncles of other species. I think all the specimens 

 found at this locality lielong to one species, variable to some extent in its 

 length and rate of tailoring. It probably is like a large gently curved 

 C^irtorcras, from six to ten inches in length, with the siphuncle on the 

 inner instead of the outer curve, and with a diameter at the aperture of 

 from one to three inches. 



Ziocaliti/ ami Foiiiintioit. — Phillipsburg, B 2, section Geol. of Can., p. 

 844 ; Quebec group. 



Collectors. — Dr. P. J. Farnsworth, and E. Billings. 



OllTIIOCEKAS CaTO. (N. Sp.) 



I>csrription. — f^hell of medium size, some-^^hat ra] idly tapering ; section 

 apparently circular; se] ta nine to the inch; siphuncle very slender, 

 cylindrical, in cuntact with the shell or nearly so ; chamber of habitation 

 deep ; surface with ratlier strong thread-like engirdling stria?, about four 

 in one line. The shell appears to be plain, but in one part there seems 

 to be some indistinct annulations. 



The specimen is 3i inches in length, somewhat flattened, evidently by 



