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base, and occasionally, at favourable moments, even of two, unequally 
curved rods. However, even as I have drawn and observed it, the 
mastax differs widely from that of A. lentiformis, and forms another 
item in favour of separating the two as distinct species. There are 
four large acuminate teeth, yet I have seen in the nearly mature 
embryo still within the egg, four teeth on one side and five on the- 
other. These, in all cases, are accompanied by a secondary series of 
five alternate acuminations situated slightly below the larger teeth, 
and much less robust in appearance, shorter, and apparently in no 
way connected with the primary series above them. A broad, band- 
like adductor muscle is conspicuous at the posterior, ventral region of 
the mastax, and produces the rolling and crushing motions of the part. 
The granular, fluid contents of the posterior stomach are often to 
be seen flowing forward through the mastax into the proventriculus, 
and back into the stomach, with which the mastax communicates 
directly. 
This posterior stomach is a subspherical sac, smaller than the 
proventriculus, and with thicker walls which, internally, are densely 
clothed with long, fine cilia. It is not always easy to determine the 
exact size and form, as it is usually obscured by the large ovary which 
seems to encircle it when in the act of producing the embryos, as it 
generally is. But in dorsal view, by careful focusing, a densely 
ciliated region is visible between the developing ovules, and in almost 
any condition of the ovary. Its entire outer surface is enveloped by 
a sheet of granular, vacuolar substance which is probably glandular. 
Traversing it longitudinally are about five oblique bands which appear 
to be muscular, but in which I have thought myself able to see at 
least traces of a lumen. 
The intestine (i, figs. 1 and 2) is immediately beneath the ciliated 
stomach, and so situated that I have not been able to see how the two 
are connected. But the intestine is on the ventral side of the body, 
and consists of a wide sac composed of three distinct subspherical 
diverticula, two lateral and large, with one central and smaller, the 
whole together forming one general cavity, the contents of the three 
parts flowing freely to and fro through the smaller central division. 
The walls are thin and are not ciliated. I have never observed the 
slightest independent motion of the intestinal walls, their movements 
seeming to be produced only by the movements of the organs above 
them, especially at the moment when the coronal cup is retracted ; 
then the contents of the sac are forced to and fro from one part to the 
other as a consequence of the crowding displacement of the digestive 
organs above it. It is reasonable to suppose, however, that the part 
must have independent contractile power to expel the excrement, but 
I have never seen this act. The intestine opens, probably by means 
of a rectum, although I have not seen it, into a subspherical cloaca, 
terminating in a conspicuous anal aperture with a much wrinkled 
margin. 
