204 



Endoceras (Naethecoceeas) ceassisiphonatitm, Whiteaves. 



-Endoceras crassisiphonatmn, Whiteaves 1891. Trans. Royal Soc, vol. IX., sect. 4, 



p. 79, pi. 6, figs. 1-4, and pL 7, fig. 1. 

 .Narthecoceraa (Endoceras ) cragsisiphonatum, 



Hyatt 1895. Amer. Geol., vol. XVI., p. 3. 



" Siphuncle (the only part of the shell known) very long and thick, 

 -attaining apparently to a length of considerably more than four feet, 

 circular in transverse section, nearly cylindrical, but alternately slightly 

 swollen and as slightly constricted at distant but regular intervals, the 

 constrictions, which cross the siphuncle somewhat obliquely, being 

 probably caused by the overlapping of the posterior portion of the necks 

 of the septa : increase in thickness very slow but regular, at the rate, so 

 far as known, of three-tenths of an inch per foot ; septa unknown, 

 -though the distances apart of the annular siphuncular constrictions and 

 their obliquity seem to indicate that the septa also were widely distant, 

 and the siphuncle itself either marginal or submarginal. Endosiphon 

 narrow and nearly cylindrical posteriorly, but widening irregularly and 

 gradually anteriorly. At the anterior end of the thickest specimen • 

 collected (which is represented in outline on Plates 6, fig. 4, and 7, 

 fig. 1 " of the paper in which the species was originally described) " the 

 diameter of the endosiphon is a little more than half that of the 

 siphuncle.'' " In another specimen (the original of figure 3 on Plate 6 " 

 of the same paper) " the interior of the narrow posterior end of the 

 siphuncle appears to be portioned off by a few transverse concave dissepi- 

 ments. 



"Collected at Lower Fort Garry by Mr. Donald Gunn in 1858; and 

 at East Selkirk by Dr. R. Bell in 1880, by Messrs. McCharles and 

 Weston in 1884, and by Mr. Lambe in 1890. 



" The most perfect specimen in the Survey collection, which it will be 

 convenient to designate as No. 1, and which is represented in outline, 

 one-fourth of the natural size, on Plate 6, fig. 1," of the paper already 

 referred to, "was collected at East Selkirk by Mr. McCharles. Its actual 

 length is three feet all but an inch, and it is obviously imperfect at both 

 •ends. It is the only specimen known to the writer in which the increase 

 in thickness is very obvious. At the smaller end its maximum thickness 

 is an inch and a tenth, and at the larger end just two inches. Its rate 

 of increase, therefore, as already remarked, is three-tenths of an inch 

 per foot. 



" Another large fragment, collected by Mr. Lambe at East Selkirk, 

 which is represented in outline, of natural size, on plate 6, fig. 1 " of 

 the paper quoted, "and which may be indicated as specimen No. 2, is 

 ■ about eight inches in length by two inches and three and a half -tenths 

 in its maximum thickness at one end and not appreciably more at the 



