536 
eight inches in diameter described by Meek and Worthen* and 
fully figured by them. ‘These figures reproduced on PI. 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 
Estonitoceras ariense as figured by Schréder, 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 ntotense, as described by Meek and Worthen, and 
of Edaphoceras (Naut.) hesperts, Kichwald,f} both with siphuncles 
nearly or exactly centren and neither having an impressed zone 
and the peculiar form described by Foord} 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. 
Lndolobus. 
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. 
EXNDOLOBUS AVONENSIS. 
NAUTILUS AVONENSIS, Dawson (Geol. of Acadia, p. 311). PI. viii, 
Figs. 36-39. 
Loc., Joggins, Nova Scotia. 
The ananepionic stage of this species, Fig. 38, Pl. viii, has a tri- 
gonal shape and the cicatrix, although necessarily exaggerated in 
* Geol. of T., v, Pl. xix. 
+ Leth Rossica, Pl. xlv, Fig. 7. 
t Cat. Foss. Ceph., ii, p. 172, Fig. 30. 
