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tion is in contact, but this is so slight that no contact furrow is 

 formed. The whorls are mostly gyroceran in the character of the 

 coil becoming excentric in the ephebic stage. 



The section is a much compressed oval, the ventro dorsal diam- 

 eter much longer than the transverse, the abdomen narrowly rounded 

 and dorsum broader, but also gibbous. The neanic stage has a more 

 rounded outline in section. 



The shell is smooth. 



The sutures have ventral and dorsal saddles with broad lateral 

 lobes in the neanic and ephebic stages. 



The siphuncle varies from centroventren to intracentroventran in 

 the neanic and ephebic stages. 



Barrandeoceras natator. 



Nautilus natator, Bill. (Can. Nat, iv, No. 6, 1859). 



Barrandeocer'as natator, Hyatt (Gen. Foss. Ceph., p. 299). 



Loc, Mingan Islands. 



This species has volutions compressed oval in section, the dorsum 

 somewhat broader than the venter ; siphuncle is extracentroventran, 

 even in the neanic stage; septa deeply concave; sutures with dor- 

 sal and ventral saddles and the lateral lobes as in other species of 

 this genus. 



The volutions are in contact, but no contact furrow was formed 

 at any age. The contact takes place as in the young of Estonio- 

 ceras perforatwn, Fig. 9, PI. vii, on the venter of the paranepi- 

 onic volution. 



The volution in the neanic stage, dorso-ventral diameter 13 mm., 

 has a much narrower venter in proportion to the dorsum than in 

 the adult. The venter was rounded at all stages and also the dor- 

 sum. The ananeanic and nepionic stage were not present in the 

 original specimen in the Museum at Ottawa, but in following out 

 the same lines it is easily ascertained that the umbilical perforation 

 must have been enormous, at least 15-17 mm. in diameter. The 

 living chamber was somewhat over one-fourth of a volution in 

 length. The whole diameter was aboul 108 mm. It was reported 

 as having been found in the Chazy limestone. 



Barrandeoceras Sternbergi. 



Nautilus Sternbergi, Barr. {Syst. SiL, PL xxxvi, xxxvii). 



Loc, Bohemia. PI. xiv, Figs. 2-5. 



This species has, as is usual in transitional species with gyroceran 



