GEROULD: CAUDINA. 
29 
ful, and even their connection, though most probable, is still 
largely a matter of inference. Hamann (’84) found in macera¬ 
tion preparations that epithelial sensory cells in the sense papillae 
of Synapta are directly continuous with subepithelial ganglionic, 
cells (Taf. 1, fig. 9), but the matter needs further investigation. 
(2) The ten buccopharyngeal nerves (Plate 4 , fig. 44) run 
radially inward from the nerve ring, through the deeper part of 
the connective tissue of the buccal region and immediately anterior 
to the buccal sphincter to the lip. The main portion of each 
nerve, lying against the axial face of the sphincter, runs thence 
backward through the connective-tissue layer of the pharynx- 
The buccopharyngeal nerves distribute branches to the buccal, 
radial, and sphincter muscles, to the epithelium of the peristome,, 
and to the muscles and epithelium of the pharynx (Plate 4 , figs. 
44, 49). The buccopharyngeal nerves consist of parallel fibers, 
among which are interspersed the nuclei of ganglionic cells. They 
do not possess the covering epithelium with supporting fibers 
which are found in the tentacular nerve trunks and the central 
nervous system. 
The distribution of buccopharyngeal nerves in the interradii, as 
they arise from the nerve ring, is seen by the following table: — 
Number of buccopharyngeal nerves 
Left- 
ventral. 
2 
Left- 
dorsal. 
2 
Dorsal. 
Q 
o 
Right- 
dorsal. 
2 
Right- 
ventraL 
1 
“ “ tentacles 
3 
O 
o 
4 
Q 
o 
2 
In case there are three tentacles ill the right-ventral interradius 
and two in the left-ventral interradius, as is true of about half the 
specimens examined in reference to this point, the number of bucco¬ 
pharyngeal nerves in these two interradii respectively would probably 
be reversed. 
A conical protuberance of the nerve ring was found in one speci¬ 
men in a series of cross sections through the anterior part of the body 
(Plate 4 , figs. 45, 47). As series of sections through the same region 
in three other cases did not show any structure similar to this, it is 
to be regarded, for the present at all events, as an abnormality. It 
has the shape of a hollow cone, the apex of which is directed forward- 
One side of the base arises from the posterior part of the abaxial 
side of the nerve ring, just at the right of the origin of the right- 
dorsal radial nerve. It runs forward through the connective-tissue 
