ON PHOEON1S OVALIS, STRETH1LL WEIGHT. 
129 
In a few individuals (PI. 7, fig. 2) a number of large eggs 
may be seen lying in the body-cavity of the noil-muscular 
region. These no doubt constitute the ovary, and the 
occurrence of this organ is of importance as evidence that 
animals in this condition are mature. 
In most of the specimens a considerable amount of granular 
tissue is visible, lying in the body-cavity, principally of the 
non-muscular region, between the alimentary canal and 
the body-wall (PI. 9, figs. 29, 33, ad.). This is the “ adipose 
body ” or “ vaso-peritoneal tissue ” of other authors ; and, 
as in other species of Phoronis, a part of this tissue 
commonly has the histological characters of a testis. I have 
not convinced myself that ovary and testis may occur in the 
same individual, and it is possible that P. ovalis is dioecious. 
If this difference really occurs between P. ovalis and other 
species (which are usually hermaphrodite) it is perhaps the 
result of the small size of the animal. 
Some of the anatomical features have been examined in 
sections ; but the material, contained as it was in the burrows 
in the shell, is not sufficiently well preserved to show the 
finer details. 
PI. 8, fig. 14, an approximately sagittal section of the 
distal end of the animal, shows the muscular region of 
the body-wall and the cup-like invagination (inv.) at its 
base. The strong muscular bands ( l . m.) are clearly seen, as 
well as the origin of the bundles from the body- wall in 
the region of the invaginated part. The epistome (ep.) is 
visible, surrounded by the tentacles, while the oesophagus ( aes .) 
is cut along the whole of its length, and is separated from 
the proventriculus (pr.) by a circular valve. The terminal 
portion of the intestine (int.) is seen by the side of the 
oesophagus; and the position of the anus (an.), which opens 
into a depression of the body-wall close to the lophopliore 
and the base of the epistome, is indicated. 
A few sections from a series cut transversely to the long* 
axis of the body have also been figured. In the first of these 
(PI. 8, fig. 16) the tentacles are seen to be arranged in the 
