26 
of the same diameter, but differs in the greater size, greater proportional 
thickness of whorl, and in the greater number of primary ribs at full size. 
The whorls are not so depressed, nor the umbilicus so large as in Otoites 
depressus Whitehouse 1 and the suture line is different. 
Horizon and Locality. In the lower part of the Yakoun formation at 
Mackenzie bay, on the north side of Maude island. 
Type. National Museum of Canada, Ottawa; holotype, Cat. No. 
9019. 
Itinsaites McLearn 
(. It-in-sa , name of an Indian chief) 
1927. Itinsaites McLearn, Trans. Roy. Soc., Canada, 3rd ser., vol. 21, 
sec. IV, p. 73. 
The genus has a more complex suture line and on the ultimate whorl, 
more secondary ribs than Kanastephanus. In all other characters, how- 
ever, it is very close. It differs from Epalxites Mascke 2 in the more dorsal 
position of lappet and tubercle. In Itinsaites the tubercle is on the inner 
edge of SI; in Epalxites it is on the outer part of SI. The position of the 
lappet is similar to that in Otoites . The umbilication is greater than in 
typical, but not in all, Otoites, and about as in Kanastephanus. The 
genotype is Itinsaites itinsae McLearn. 
Itinsaites itinsae McLearn 
Plate XV, figures 2, 3 
1927. Itinsaites itinsae McLearn, Trans. Roy. Soc., Canada, 3rd ser., 
vol. 21, sec. IV, p. 73, PL 1, fig. 7. 
Diameter. 
51-0 
27-6 
38-9 
49-6 
23 
71 
48-4 
28-2 
44-0 
48-6 
450 
28-8 
47-9 
46-4 
43-4 
28-4 
48-8 
46-0 
35-2 
29-7 
57-6 
45-0 
33-8 
30-1 
57-5 
43-4 
Height, whorl 
Thickness, whorl 
Width, umbilicus 
Primary ribs 
Secondary ribs 
The umbilicus increases on the ultimate whorl; perlatumbilicate. 
Whorl suture begins to move outside of line of tubercles somewhat posterior 
to the last septum, which is at a diameter of 36-5 mm. The inner whorls 
are depressed, much thicker than high. On ultimate whorl the proportional 
thickness decreases and the venter becomes well rounded. The lappets 
are long and lateral in position. The living chamber is about nine- 
sixteenths of the ultimate whorl. There are 23 primary and 71 secondary 
ribs on the ultimate whorl. The stage of reduction to two secondary ribs 
per each primary, attained, or nearly attained, in all species of 
Kanastephanus, is not reached in I. itinsae: in the first three-quarters 
of the ultimate whorl there are three and a fraction secondary ribs to 
each primary, arising by trifurcation or bifurcation and intercalation. 
1 Jour. Roy. Soc. Western Australia, XI, p. 6, text fig. 4, PL I, figs. 4, 5, 6 (1924), 
2 Set Buckman, S. S.: Type Ammonites, III, Pis. 151, 159 (1920). 
