6 The American Geologist. July, 1895 
ing of the cicatrix. At the end of this substage or the begin- 
ning of the neanic (adolescent) stage the endosiphon was 
plugged lip internal]}" with calcareous matter in yanno, as 
described above. The second endocone belongs to the first or 
ananeanic substage when the siphon begins to contract and 
there is no endosiphon. 
Among the specimens there was another figured bj'^ Prof. 
Clarli^e only in part in his section, figure 4, to show the radial 
deposits. This proved so very peculiar and interesting that 
I have given an enlargement in plate I, figure 2, with the cen- 
ter omitted where Clarke's section was taken. The sheath in 
this is complete but has a rounded termination. The two en- 
docones are present as in Clarke's figure 8 and the structure 
of the organic filling is the same but less dense than in that 
specimen and not so opaque. The interest centers in the pe- 
culiar density, rounded termination, and structureless aspect 
of the filling of the second endocone, immediately apicad of 
the tip of the sheath, and the contrast between this and the 
triangular space between this and the first endocone. In this 
triangular space the filling is looser and subcrystalline show- 
ing rapid deposition as if done by a retiring and comparative- 
ly rapidly moving fleshy sheath. 
In completing the end of this section I opened up the en- 
dosiphon and, finding that the trace grew narrower nearer 
the center of the tip, ceased grinding. Subsequentl}" upon 
close study by reflected light from a sheet of white paper I 
succeeded in seeing the dark trace of the endosiphon still be- 
low the surface but penetrating, as shown in figure 2, the en- 
tire thickness of the first endocone. Then by taking ofi' a 
little more I found the endosiphonal walls below continuous 
as given in the figure, but the dark shade still allowed to re- 
main in this figure has become less noticeable. 
This observation shows that the endosiphon is not always 
precisely tubular and sometimes is not in the exact center so 
that it may be easily obliterated when rubbing down a speci- 
men and may be present when not visible in a section taken 
through the center. That it was like that of figure 1, open 
to the exterior, is shown by the dark color of the matrical fill- 
ing, which agrees with that of the sheath above, and it also 
belongs to the age of the first endocone as in that specimen. 
