501 
stages of growth. The large number and great variety of form of 
these smooth species, while still maintaining this difference of the 
later stages of growth, shows that this separation indicates a natural 
distinction, and I have therefore placed all under the generic name 
of Schroederoceras, to commemorate that author’s distinguished 
services in this field of inquiry. 
DISCOCERAS ANTIQUISSIMUM. 
CLYMENIA ANTIQUISSIMA, Eichw. (Urwelt Russ/., ii, Pl. iii, Figs. 
£6,°17)- 
This is a peculiar species represented in the collection in the 
Museum of Comparative Zodlogy by a specimen from Porsgrund, 
in Norway. It is heavily costated, as in the figure given by Eich- 
wald, and these costations are deeply impressed upon the cast 
throughout the earlier stages and in the ephebic stage. They 
degenerate only in the gerontic stage. 
The abdomen is broader than the dorsum and the sides convex 
and evenly rounded. ‘The costa are very prominent and sharply 
defined, as in the original figure. The sutures, as far as these could 
be seen, appeared to be similar. ‘The size was also similar and the 
last whorl in close contact, as in Eichwald’s figure of this species. 
The specimen described had reached the anagerontic stage, the 
costee having disappeared, or, at any rate, ceased to be reflected on 
the cast near the end of the last whorl, whereas in all previous 
stages, except probably the earliest nepionic, they are almost 
equally prominent on both the cast and the shell. 
The siphuncle is subdorsan at all the stages observed from what 
appeared to be the second to the third and fourth whorls. It is 
quite large, especially on the second whorl. 
The neanic whorl is digonal and heavily costated. The ephebic 
and gerontic whorls are depressed ovals, the abdomens broader 
than the dorsi. The section of the gerontic volution had ventro- 
dorsal diameters 25 mm. and transverse 35 mm., without the shell. 
The whole diameter of this specimen was about 110 mm. 
DIscOCERAS GRAFTONENSE. . 
LiruITES GRAFTONENSIS, M. et W. (Proc. Acad. Philadelphia, 
1870). 
LITUITES GRAFTONENSIS, M. et W. (Geo/. /2., iii, vi). 
