104 



coarser ones. This specimen was carefully ground down on the ventral 

 side in such a way as to give a longitudinal section through the centre of 

 the siphuncle and to show the edges of 22 septa, as represented in fig. 8a. 

 These septa are about one millimetre apart at the bmaller end, and four 

 millimetres at the larger. Between the septa the siphuncle is not en- 

 larged. The other specimen from Durham (fig. 9), which is a little over 

 two inches and a half in its maximum length, consists of the greater part 

 of the body chamber and the posterior half of the septate portion of the 

 shell, both almost completely covered with the test. The venter and 

 dorsum are very slightly compijessed, and each of the beautifully preserved 

 transverse striae upon the test forms a very faint hyponomic sinus on 

 the median line of the venter. 



In 1890 Mr. Townsend obtained at Elora a large but not very well 

 preserved specimen, nearly four inches and a-half in length, which is also 

 belived to be referable to C. Orodes. It is somewhat compressed on the 

 venter and dorsum, and its siphuncle is apparently exogastric and almost 

 marginal. It is very similar, in general outline, to large specimens 

 of Oncoceras Pettiti, Billings,* from the Niagara limestone at the North 

 Gore, Grimsby, Ontario, but the siphuncle of the latter is inflated be- 

 tween the septa. 



Phragmoceras Hector, Billings. 



Phragmoceras Hector, Billings ..1862. Geol. Surv. Canada, Pal. Foss. , vol. I., pt. 



1, p. 163, fig. 147. 



Hespeler and Gait, E. Billings, 18.57 : one cast of the interior of the 

 shell from each of these localities. The specimen figured by Billings is 

 labelled Gait, not New Hope (or Hespeler as it is now called) as 

 stated in the first volume of the " Palseozoic Fossils.'' and both specimens 

 show the shape of the aperture. 



^ Hyatt, in his "Genera of Fossil Cephalopods,"t maintains that Phrag- 

 moceras is a mere synonym of Goviphoceras, and divides the latter genus 

 into six genera, based exclusively upon the characters of the aperture. 

 Zittel, on the other hand, in the second volume of his " Handbuch der 

 Palaeontologie," places Gomphoceras in the family Orthoceratidaj and 

 Phragmoceras in the Cyrtooeratidse. Fischer, in his Manuel de Conchy- 

 liologie (1883) regards the two genera as distinct and places both in the 

 Nautilidie. The characters which have so long been used to distinguish 

 Phragmoceras from Goinphoceras appear to the writer to be still valid 

 and of more structural and systematic importance than the modifications 

 of the aperture upon vrhich Hyatt's six genera are based. 



'Catalogue of the Silurian Fossils of the Island of Anticosti, p. 86. 

 tProceedinga of the Boston Soc. Nat, Hist., April 4, 1883, vol. XXII, p. 277. 



