322 Scientific Proceedings, Royal Dublin Society. 



tentacles. Beside this evidence of the hexamerous arrangement 

 may be adduced the number of mesenteries, which in this species 

 may generally be counted through the base of the living animal, 

 as the lines of their insertions appear as rich pink on a gray or 

 drab ground. An examination of the base shows plainly that 

 these lines correspond with the arrangement of the warts. All the 

 specimens we have seen had two oesophageal grooves, each with its 

 two conspicuous tubercles. 



A longitudinal section through the body wall exhibits a very 

 similar appearance to what we find in Bunodes thallia (PI. v. fig. 2). 

 The evaginations are just as conspicuous, and the circular muscle is 

 strongly developed ; it is endodermal, and projects into the body- 

 cavity as a thick cord. In a transverse section of this cord the 

 mesoglcea is seen to be divided into two main branches, the smaller 

 of which is superior, and lies next the disk. Each branch has 

 many ramifications (PI. v. fig. 3). In the oral disk, near the 

 oesophagus, the mesoglcea is again thrown into pleatings, and thus 

 is formed a second circular muscle immediately enclosing the 

 mouth (PI. iv. fig. 2x). 



Some of the specimens on which these observations were made, 

 while under examination, gave birth to a number of young. "We 

 killed these immediately on their ejectment from their parents' 

 mouths, and examined them by transverse sections. In the region 

 of the oral disk twelve mesenteries, arranged in six pairs, two 

 pairs being the directive mesenteries, reach the oesophagus ; this 

 arrangement, it will be seen, corresponds to that in the same 

 region in the genus Halcampa. A section made a little lower 

 down shows that four of these twelve mesenteries stop short of the 

 oesophagus, and so we have the arrangement reproduced which 

 obtains in the lower sections in the genus Halcamjxi. The 

 arrangement of the eight perfect mesenteries of Bunodes verrucosa 

 at this stage, just as Professor Haddon (these Proceedings, vol. v., 

 p. 479) has proved in the case of the genus Halcampa, corresponds 

 precisely to the arrangement in the genus Edwardsia. As the 

 sections get lower, the number of mesenteries increases, but the 

 pairs of " secondary mesenteries " do not appear simultaneously in 

 each of the exocceles. At the level of about the middle of the 

 oesophagus, a pair of very small mesenteries appears in the 

 exocceles on either side of that pair of directive mesenteries, whose 



