40 



millimetres in their distance apart, and as close together on the ventral 

 or siphonal side as they are on the dorsal or anti-siphonal : siphuncle 

 marginal or nearly so, moniliform and about eight millimetres broad ia 

 its greatest diameter on the septum next to the body-chamber. 

 Chamber of habitation ovate in outline in transverse section, narrowest 

 on the siphonal side, expanding very slowly in its dorso-lateral diameter 

 and broadest in that direction at or a little below the mouth : maxi- 

 mum height of the same chamber in some specimens about equal to, 

 and in others much less han, its greatest dorso-vontral diameter, its 

 venti-al side being alwaji-s shorter than the dorsal. Aperture linear 

 and narrowly contracted in the middle for a distance of a little more 

 than an inch, expanded and nearly circular at both ends, the anti-si- 

 phonal expansion being much larger than the siphonal. Surface of 

 the septate portion and of the posterior halt of the chamber of habita- 

 tion marked by very faint, longitudinal, rounded ribs. 



Hespeler, T. C. Weston, 1867 ■ Elora, loaned by the Tmstees of the 

 School Museum per Mr. David Boyle: Durham, Mr. J. Townsend, 1883. 

 A single cast from each of these localities, one of which is that of the 

 body chamber only, showing the shape and position of the siphuncle, 

 while the others are casts of the same chamber with from six to nine 

 septate chambers attached. As the posterior end of each happens to 

 be imperfect, it is difficult to estimate the exact amouut of their 

 curvature. 



These specimens resemble the P. Nestor of Hall, from the Niagara 

 Gi-oup of "Wisconsin, much more closely than they do the P. Hector of 

 Billings, from the Gruelph Formation, especially in the shape of the 

 aperture and in the contour of the chamber of habitation. They 

 appear to indicate a mere local a,nd atratigraphical variety of P. Nestor, 

 which can most readily be discriminated from the type of that sjiecies 

 by its much straighter form, — in consequence of which the edges of 

 the septa are nearly equidistant all round, — and by its faintly ribbed 

 outer surface. This latter character, however, does not seem to be 

 constant, for the ribbing is only to be seen in places on two of the 

 Canadian specimens, and not at all on a third. The cast from Blora 

 which on the whole should probably be regarded as belonging to this 

 variety of P. Nestor, is not only perfectly smooth but its dorsal aperture 

 is produced into a short tube. 



A specimen in the Museum of the Survey which was collected by 

 Dr. E. Bell in 1862 at L'Anse a, la Barbe in the Bale des Chaleurs from 

 rocks of nearly if not quite the same geological horizon as the Guelph 

 Forn-iation, can scarcely be distinguished from the typical form of 

 f, Nestor, 



