461 
the flat zone being narrower than the transverse diameters imme- 
diately internal to this. This may be due to compression, since on 
the septate portion the lateral curve from the abdomen to the um- 
bilical shoulders show the somewhat flattened aspect given in 
Saemann’s figure. The umbilical shoulders are rounded. The 
abdomen not so broad as the dorsum, that is not so broad as the 
transverse diameter through the umbilical shoulders. 
The cast shows faint broad fold-like costations bending apically 
which were more prominent on the shell, as is shown by other speci- 
mens from the same locality. Saemann’s figure is correct in outline 
and proportions, but it, is incorrect in that it does not give the 
sutures which are apparent on the original, and it also brings the 
cast of the whorls in close contact, whereas these are separated by 
the thick dorsal and ventral shell layers. The whole surface of the 
cast is also erroneously given, since it is marked by obscure costa- 
tions, which must have been more prominent upon the exterior of 
the shell. These are more prominent in the young than upon the 
full-grown whorls. The sutures have well-marked ventral and dor- 
sal lobes and lateral lobes with saddles at the abdominal angles an«l 
umbilical shoulders. ‘The sutures are numerous and close together 
as in most species of this group and in Trocholites. 
The siphuncle is nearer the dorsum than that given in Fig. re. 
The apex is smaller than in the original of Figs. r¢ and 1¢@, and 
the umbilical perforation smaller and the rate of increase by growth 
less, so that the species is smaller than Saemanni. 
The living chamber in angu/atus is free as figured by Saemann on 
the outer part only. In the original of Fig. 1c-d it is free for 
nearly the entire length. 
The prominent coste of the true Desc. antiguissimum are not 
present in this shell nor in its allies, and the differences in formare 
supplemented by the close coiling of the living chamber in an¢trguzs- 
simum. 
Saemann’s original is 91 mm. in diameter, and has somewhat 
more than threeand ahalfvolutions. The living chamber measured 
along the median lateral line is 53 mm. in length from aperture to 
suture. ‘The transverse diameter of the septal floor is 26.5 mm., 
the dorso-ventral diameter in median plane is 20.5, both without the 
shell. The aperture is narrower in proportion to the ventro-dorsal 
diameter, owing to the flaring of the lips and the slight constriction. 
Only one-half is preserved and it is slightly distorted ; it may bea 
