﻿405 



The incomplete living chamber occupied 75 mm. of this free part 

 as measured above the median lateral line from the broken edge to 

 the imperfect remnant of the septal floor. 



The transverse diameter of the termination of the third whorl 

 was 15 mm. without the shell, the breadth of the side 10 mm., the 

 ventro-dorsal diameter in the mesal plane, as estimated, was of 

 about the same length. The transverse diameter about the middle 

 of the last quarter of the fourth whorl was 22 mm., the ventro- 

 dorsal in the mesal plane was 17 mm. both without the shell. 



The shape of the living chamber must have been greatly altered 

 near its termination. The fragment of mould of one side and part 

 of the dorsum preserved shows that the impressed zone had become 

 narrowed and disappeared completely. The dorsum remained 

 slightly flattened, but this flattening given in the restored section, 

 Fig. 3, PI. vii, is probably greater than it was in the fossil. The 

 lines of growth on the dorsum of the first part of the free living 

 chamber have such a faint sinus that they would ordinarily be de- 

 scribed as straight, the lateral crests are much reduced, the ventral 

 sinus was not visible, but it also probably became reduced or 

 shallower. The transverse diameters were also much reduced, and 

 aspect of the aperture changes so that the ventro-dorsal diameter is 

 much longer than the transverse. The outline given may be de- 

 fective in making this diameter somewhat too long and the abdomen 

 not quite flat enough, but certainly there is an entire change in the 

 proportions of the whorl and an approximation to this reconstructed 

 outline. 



The sutures do not differ materially, if at all from those of 

 Saemanni so far as could be seen. They are visible on the third 

 whorl and had the usual curvatures. The two last on the fifth whorl 

 were visible on the dorsum and partly on the side. These had a 

 deep dorsal lobe, with saddles and lateral lobe as in Saemanni, and 

 were very interesting, since they showed that the dorsal sutures had 

 not been immediately affected by separation of the whorls. The 

 last suture is given in Fig. 1, on PI. vii. 



The zone of impression is fainter, but still perceptible in the dor- 

 sum of the first part of the living chamber, but has entirely disap- 

 peared on the latter part of the same. It is more strongly marked 

 on the dorsum of the third and early part of the fourth whorls than 

 on the latter part of the fourth, but it is broad and still quite dis- 



