467 
subcostal in aspect, but are somewhat exaggerated in Fig. rr. In 
the ephebic stages these subcostz are less prominent and do not 
have any corresponding ridges on the cast, which is smooth. The 
venter is also less elevated, the ventro-dorsal being less in proportion 
to the transverse diameters and the whorl assumes the broad de- 
pressed outline in section of this species. 
SCHROEDEROCERAS RAROSPIRA. 
CLYMENIA RAROSPIRA (pars) Eichw. (Leth. Rossica, Pl. 1, Fig. 1a-4, 
Fig. 3; not Fig. 2a—d, nor Fig. 6a, 4, c*). 
This species has the aspect of Schroederoceras Saemannt on the 
latter part of the second and third whorl, but the early part of the 
same whorl in section is rounded and without a zone of impression. 
The whorls increase faster by growth in the ventro-dorsal diameters 
than in Saemanni. If Eichwald’s figures can be relied upon the 
species are distinct. The distribution of the prominent striz of the 
neanic stage is instructive. They occupy all of the first whorl ex- 
cept the apical part and are lost upon the last half of the second 
whorl, persisting somewhat longer than in Saemanni or angulatum. 
The siphuncle is depicted as very large, and according to the figure 
is nearer the dorsum in the first and second whorl than it is in the 
same age in Saemanni. ‘The faster increase in dorso-ventral 
diameters makes the adult somewhat larger in diameter of the coil 
at the same age. 
The fact that the last volution is not free at the end shows proba- 
bly that the specimen: figured had not reached the gerontic stage of 
degeneration. It is of course to be expected that some species of 
Schroederoceras never become uncoiled, and this may be one of 
these. Eichwald’s Fig. 14 also shows that the impressed zone is 
deeper on the second whorl in the anephebic stage than it is sub- 
sequently on the third whorl in the parephebic when a tendency 
towards uncoiling begins to show itself in this way. ‘The sutures 
as shown in Figs. 3a, 4, ¢, are like those of Saemannt. 
SCHROEDEROCERAS TERES. 
Lir. TERES, Eichw. (Si/. in Esthland, p. 105). 
Lit. TERES, Dewitz (Schrif. physical-okonon. Gesell,, Koénigsberg, 
5 a il eae gel oh Fey 8) 
Lit. TEREs, Schroeder (zdid@., xxii, Pl. ii, Fig. 2). 
Discoc. TERES, Schroeder (zécd., xxili, p. 96). 
* See Trocholitoceras Eichwaldi. 
