142 SIDNEY F. HARMER. 
stomach were growing out from the other (posterior) side of 
the bud in the manner described by Haddon.! 
The tentacles soon become arranged in the form shown in 
fig. 2, the bilateral series bending away from the opercular 
side of the zocwcium on each side as far as the emargination 
which marks the point from which the stomach and intestine 
have been evaginated. The retractor-muscles of the polypide 
are by this time developed asa group of fibres converging from 
the polypide to the ‘“ brown body.” 
The tentacles next rotate completely, so as to point towards 
the aperture, and their bases now form a simple circle, the 
plane of which is transverse to the long axis of the zocecium, 
and at right angles to its opercular surface (fig. 3). The 
tentacle-sheath has become prolonged along the strand of 
tissue connecting it with the operculum, and has met a semi- 
circular thickening lying beneath the operculum, and destined 
to give rise to the new aperture. 
The apex of the evagination which forms the rectum, intes- 
tine, and stomach corresponds to the apex of the cecum. It 
is attached to the strong funiculus already described. Fig. 3 
(305 hours from the beginning of the experiment) shows the 
commencement of the pharynx and cesophagus as a new out- 
growth from the front surface of the bud. The “ brown body” 
is more spherical than before, and has retreated to the proximal 
end of the zocecium, a position which it normally occupies at 
this stage. The tentacle-sheath has met the developing 
aperture. 
At the 353rd hour the two green parts of the “‘ brown body” 
of the individual shown in fig. 3 were commencing to fuse. 
The end of the cecum was of a lighter colour than the rest of 
the alimentary canal, and had passed, guided by the funiculus, 
very nearly as far as the “ brown body.” 
At the 376th hour (fig. 4) this part of the cecum had met 
the “brown body,” in which the two green masses (seen 
through the “brown body”) were in the act of fusing; the 
‘‘ brown body” was commencing to be retracted away from the 
‘ Loc. cit. 
