-33- 



recognized by their long, curved, lateral oillated chambers 

 (1.0. h, ) , 



In Fig. 6 e the median pairs of cell-groups are seen 

 in a mid-ventral position (m.o.g.) as they are followed in an 

 anterior-posterior direction, again in a mid-dorsal position 

 (m.c.g',) as they are followed in a posterior-anterior direction, 

 and again in nearly the centre of the gland at la.o.g*'. as they 

 are followed toawrds the posterior end again. This is easily 

 understood by noting the position of the line e In Fig. 6 k, 

 which shows that the section is cut at the point where the poste- 

 rior-anteriorly dlreoted part of the median cell-groups (m.c.g'.) 

 turns ventralward to pass again towards the posterior (m.c.g''.). 

 The central ciliated chamber (ra.c.h.) is thus seen, is this sec- 

 tion, to be continuous from the dorsal (m.c.g'.) to the middle 

 (m.c.g'',) position of the median cell-groups. The general char- 

 acter of the various groups and layers of cells remains about 

 the same in all four of these sections, so that is will be only 

 necessary to speak of their position and arrangement in the sec- 

 tions. 



The next section (Fig. 6 f) cuts the median cell- 

 groups in four places, as is shovm In Fig. 6 k, at m.c.g. in the 

 anterior-posteriorly directed portion, at m.c.g'. in the dorsal, 

 posterior-anterior portion, at m.c.g''. in the part that is di- 

 rected again towards the posterior end, and at m.c.g'''. in the 

 last whorl of the coil which is directed tov/ards the anterior 



