﻿464 



be seen, but it was clear that the impressed zone had become nar- 

 rower and shallower. The termination of the living chamber being 

 also absent, it could not be ascertained whether it finally disappeared 

 or not on the dorsal rim of the aperture. 



Schroederoceras tubulatum, ii. s. PI. vii, Figs. 1-3, and PI. xiv, 

 Figs. 6-12, >h 



Loc, Brevig, Norway. 



This species was included by Saemann under the head of angu- 

 latum, but it has much broader whorls, increases more slowly in 

 size and the free part of the whorl is longer, not only the living 

 chamber but a considerable portion of the septate whorl being free. 



A cast of the latter part of the first or first part of the second 

 whorl is costated, and the narrowness of the side shows that the 

 young whorl was not so broad ventro-dorsally as in angulatus at the 

 same stage. 



One specimen shows the living chamber in the ephebic stage be- 

 fore the uncoiling begins. This is of about the same age as that 

 figured by Saemann in his angulatus, Section id. The ventro- 

 dorsal diameter of the septal floor of this is 26 mm., and the trans- 

 verse about 32 mm. The venter was the broadest part at this stage 

 as it is in the early ephebic stage of angulatum. The umbilical 

 shoulders do not exist even in the rounded form that they take on 

 in the adult of angulatus and in the ephebic and gerontic whorls of 

 Saema?ini. The sides incline or diverge outwardly more decidedly 

 and are flatter than in Saemanni at the same stage. 



The shell has coarse lines of growth upon this living chamber at 

 more or less irregular intervals, with finer lines between them, and 

 at still rarer and less regular intervals there are the usual narrow 

 ridges which are the remains of the costse of earlier stages. The 

 ventral sinus is broader and deeper than in angulatus or Saemanni 

 at the same stage, and there is a deep sinus in the impressed zone 

 on the dorsum with a shallow subacute V shape. 



The type of the species is the specimen showing the extended last 

 whorl figured in this paper, PL vii, Fig. 1. 



According to my estimate this specimen must have had at least 

 five complete whorls. The diameter of the coiled part was proba- 

 bly about 118 mm., and this is estimated to contain nearly five 

 volutions, the length of the free part was over 115 mm. measured 

 along the median lateral line, along the dorsal line of this mould 

 of the outer whorl it could be measured more readily as 105 mm. 



