404 COI^TKIBUTIONS TO CANADIAN PALAEONTOLOGY. 



Siphuhcle nearly central, oylindriual or nearly so, two lines in thickness 

 where the diameter of the shell is sixteen lines." 



" The l)est specimens in tlie colleotiun (those from one and a half to 

 two feet in length) show none of the septa except in the five or six inches 

 of the smaller extremity. One only, shows a single seplura which is five 

 and a half lines deep where tlie diameter is two inches and a quarter. In 

 the same locality, and in the same state of preservation, were found a 

 number of fragments in which there are eight or nine septa in a length of 

 four inches, where the diameter is between two and three inches. I think 

 these all belong to the same species." 



Mr. Billings does not say whether his types of 0. Anax a.r<i ivom the 

 Hamilton formation or Corniferous limestone, but several specimens of a 

 large Ortli.oceras, in the Museum uf the Survey, which are labelled as hav- 

 ing been collected in the Township of iiosancjuet by Mr. J. Richardson, in 

 1855, and by Mr. Johnson Pettit, in 1858, are evidently the originals of 

 the foregoing desciii)tion. Six oi these specimens, which are probably 

 some of the "fragments " referred to, are much tuo impei'fect for specific 

 determination, but fi\e are fine and apparently typical but very badly 

 preserved examples of 0. Aiiax. The approximate dimensions of three of 

 these latter is as follows, commencing with the largest. No 1 (which is 

 very slightly curved), total length twenty-one inches, of which between 

 about four inches and tliree-i|uarters at the smaller end are distinctly 

 septate; JSlo. 2, total lengt^h sixteen inches and three-quarters, of which 

 between three and four inches are septate; and Nri. 3, total length 

 fourteen inches and a half, of which about two inches are septate. A 

 fourth sjiecimen, which is not more than five inches in length, is also pro- 

 bably the one upon which Mr. Billings based the statement that the 

 siphuncle of 0. Aiia.i: is "two lines in thickness where the diameter of the 

 shell is si-xteen lines." 



Judging by these five specimens, and by Mr. Billings's description of 

 the species, it would seem that the only distiucti\'e cliaracter of 0. Anax 

 is the apparent length of its chamber of habitation, a character which is 

 not exhibited in any of the Devonian species of Ortlioceras described and 

 figured by Hall in the secontl part of the fifth volume of the Paheontology 

 of the State of New York, and one which is very possibly due to the 

 imperfect preservation of the specimens. 



A. 2. r'liamVjer .if !i;il)itation iiiucli whortHr than the sejitaN^ portion of the shell. 

 (JuTiiocnEAs Lambtonjcnsh (Nom. prov.^ 

 Plate 4y, figs. 1 and 1 a 



Shell longicone, increasing very slowly in thickness, and circular in 

 transverse section : chamber of habitation nearly cylindrical, apparently 



