466 
tinct just before the whorl becomes free on the last quarter of the 
fifth volution (Fig. 2). 
The nepionic stage of this species is given in Figs. 6-7, Pl. xiv. 
The advent of the hyponomic sinus can be seen in the lines of 
growth of the metanepionic substage in the front view, Fig. 6. The 
umbilical perforation is larger than it appears to be in the side view, 
Fig. 7, because it is in part overlapped by the inward growth of 
the umbilical zones of the paranepionic volution. 
The lines of growth are entire and very fine lines on the anane- 
pionic and metanepionic substages, and there are no longitudinal 
ridges. The sides are convergent and rounded, and the abdomen 
is rounded and narrower than the dorsum in these substages. At 
the beginning of the paranepionic the abdomen becomes suddenly 
flattened, the sides also tending to become flatter and the whorl 
spreads laterally very fast, the venter becoming wider than the 
dorsum. Slight crenulations also appear, and in consequence of 
these faint longitudinal lines may be seen with a magnifier. 
Regularly spaced transverse lines are first noticeable in the 
paranepionic forming the forward edges of broad laminz on the 
surface and having finer lines of growth between them, as in Fig. 10, 
Pl xiv: 
The septa in this substage are deeply concave and have broad 
ventral saddles divided by narrow V-shaped central ventral lobes, 
as in Fig. 10, Pl. xiv. There are shallow lateral lobes and dorsal 
lobes in the contact furrow. 
The siphuncle is propiodorsan in this substage as givenin Fig. 9, 
but was not seen in earlier ages. It is slightly nearer the dorsum in 
the succeeding stages of development of this specimen. 
A Gistinct dorsal furrow appears in this shell in the early part of 
the paranepionic and deepens until replaced and enlarged by the 
contact furrow. Contact takes place upon the area of the scar, but 
not on the dorsal side of this area. I was not able to define the ex- 
act line of contact because the apex had been slightly fractured in 
making the preparation, but it was quite clear that contact did not 
occur upon the dorsum of the ana- nor metanepionic substages as it 
does in Trocholites. The involution is greater and the contact 
furrow deeper in the ananepionic substage, where it begins, than 
at any subsequent substage, as shown in Fig. 8, Pl. xiv. 
In the meta- and paraneanic substages the more prominent lines 
of growth described above on the edges of the broad bands become 
