482 
tained. The aperture was not very plainly discernible, but was ap- 
proximately as given in the figure. 
The ephebic stage has raised lines or bands of growth straighter 
on the sides than in the gerontic stage, which has evidently begun 
on the last whorl. This has moderately heavy ridges which are re- 
flected on the cast of the living chamber. 
It is separable from Schroederoceras Hatont by the broad whorls 
of the young and the near approximation of the siphuncle to the 
dorsum in the neanic stage. 
TROCHOLITOCERAS (?) EICHWALDI. 
CLYMENIA RAROSPIRA, Eichw. (Leth. Rossica, Pl. 1, Fig. 2, a, b, c, 
and 6) a, b, c; not Fig. 1, a-b, and-3): 
The descriptions and figures of Eichwald show conclusively that 
this is widely different from Schroederoceras rarospira and is nearer 
to true Trocholites. The form of the whorls in the young, the slow ~ 
rate of increase in the dorso-ventral diameters, the rotundity of the 
sides and abdomen in the young and even in the full-grown whorls, 
the small diameter and close approximation of the siphuncle to the 
dorsum, make this shell very like a species of Trocholites. 
On the other hand, the sutures are more sinuous, having deeper 
ventral and lateral lobes than are common in that genus. The 
living chambers are less than one-fourth of a volution in length, with 
the lateral crests of the aperture most prominent about the centre of 
the lateral aspect. 
The question of affinity can of course only be definitely settled 
after the development of the siphuncle in the apex of the conch has 
been studied. The appearance of the umbilicus, as shown in Fig 6 
of Eichwald, is similar to that of other species of this genus, but this 
of course may be due to erroneous draughting. 
Trocholttes. 
This genus has been fully described and correctly defined by 
Schréder,* and the following description is largely taken from his 
work and adapted to the needs of this work. The shell of the ne- 
pionic stage, as first shown by Holm,t is so closely coiled that no 
umbilical perforation is externally visible. Observations of two 
young specimens of T. described below have, however, shown the 
* “Unters. ub, sil. Ceph.,’’ Pal. Abt., Dames et Kayser, N. F. (current Vol. v), heft 4. 
7 “Sil. Ceph.,’’ Pal. Abh., Dames et Kayser, iii, Pl. vy, Figs. 9, 10 and 11. 
