324 



Ortlwceras, which Hyatt includes in his genus Spyroeeras. Its surface 

 ornamentation " appears to be decidedly diiferent from that of any of the 

 small annulated species of Ortlwceras from the Trenton limestone of the 

 State of New York described and figured by Hall in the first volume of 

 the Palaeontology of that State. 0. bilineatum, Hall, is a much larger and 

 more robust species, with coarser annulations and two series of longi- 

 tudinal ridges or linear elevations. 



"In 0. claihratum, Hall, the longitudinal markings are very minute and 

 crowded, and are said to consist of ' sharp elevated lines distant -^-^ of an 

 inch,' or very little more than half a millimetre apart. There are, also, 

 no comparatively coarse and distant longitudinal ribs or ridges in 0. textile. 

 Hall, and in that species the transverse annulations are represented as 

 both prominent and angular. 



{Ortlwceras fTestont, which was described in the same paper as 0. Beaiipor- 

 tense, and which has not been figured, is based upon a specimen from the 

 Trenton limestone at Montreal, which the writer now thinks to be part 

 of the siphuncle of an Endoceras. The "distant and very obliquely flattened 

 annulations " of the exterior of this specimen are probably septal rings, 

 like those of aPiloceras, and the obscure indication of a supposed siphuncle, 

 as exposed in a transverse fracture, is probably part of the endosiphuncle.) 



C. FROM THE DEVONIAN ROCKS OF ONTARIO. 



Orthoceras Walpolense, Whiteaves. 



Plate 33, fig. 3. 

 Orthoceras Walpolense, Whiteaves 1898. Ottawa Naturalist, vol XII, p. 125. 



'^ Shell small, longicone, straight, slender and increasing very slowly in 

 thickness, slightly and perhaps abnormally compressed. Test unknown ; 

 surface of the cast marked by thin, acute, transverse, annular ridges, 

 which are much narrower than the grooves between them. Septa, and 

 shape of the siphuncle, unknown. 



" The largest specimen known to the writer was collected many years 

 ago by J. De Cew in the Corniferous limestone of lot 6, concession 14, 

 of the township of Walpole. It is about eighty-four millimetres (3\ inches) 

 in length, by six mm. in thickness at the smaller end and about fourteen 

 at the larger. Near the smaller end there are about ten annulations and 

 near the larger end about six, in a length of ten mm. The only other 

 specimen that the writer has seen, is a fragment about an inch and a half 

 in length, from the same formation, and labelled lot 42, concession 1, 

 Cayuga, which is probably referable to this species. It has about eight 

 annulations in a length of t«n mm., at the larger end. 



