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eight inches in diameter described by Meek and Worthen* and 

 fully figured by them. These figures reproduced on PL vii, 

 Fig. 22-24, show the generic differences of this species and the 

 forms on the same plate, which are good examples of the genus 

 Estonioceras. Edaphoceras differs in having non-involute whorls 

 without an impressed zone and a more completely digonal outline 

 in transverse section of the full-grown volution. 



The sutures have ventral lobes, saddles at the lateral angles and 

 dorsal lobes with slight median saddles if the figure is correct. 



The siphuncle is centren in the adult. 



Notwithstanding the close resemblance of the type species to 

 Estonioceras ariense as figured by Schroder, I doubt whether this 

 Carboniferous type has direct genetic connection with Estonioceras 

 of the Silurian. Until the young, are known it will be impracti- 

 cable to settle this question, but at present the close-coiled shells 

 of Edaphoceras niote?ise, as described by Meek and Worthen, and 

 of Edaphoceras (JVaut.) hesperis, Eichwald,f both with siphuncles 

 nearly or exactly centren and neither having an impressed zone 

 and the peculiar form described by FoordJ as Solenocheilus cale- 

 donicus which is similar but has a slight impressed zone, all point 

 to a separate phylum from that of Estonioceras. 



I do not, however, wish to imply that they did not arise from the 

 same common origin, possibly some form of Eudoceras, but simply 

 that Edaphoceras does not appear to be a direct descendant of 

 Estonioceras. 



Endolobus. 



This genus was first described in Genera of Fossil Cephalopods,. 

 and subsequently in the Second and Fourth Ann. Rept. GeoL Surv. 

 of Texas. 



Unluckily I have never been able to study the young of the type 

 Endolobus spectabilis of Meek and it may be that none of the spe- 

 cies referred to this genus really belong to it. 



Endolobus avonensis. 



Nautilus avonensis, Dawson {Geol. of Acadia, p. 311). PI. viii r 

 Figs. 36-39. 



Loc, Joggins, Nova Scotia. 



The ananepionic stage of this species, Fig. 38, PI. viii, has a tri- 

 gonal shape and the cicatrix, although necessarily exaggerated in 



* Geol. of III, v, PL xix. 



f Leth Rossica, PL xlv, Fig. 7. 



X Cat. Foss. Ceph., ii, p. 172, Fig. 30. 



