
No. 428.] PHARYNX. IN PLANARIA MACULATA. 641 
seems to have little or no influence on the position of the new 
pharynx. The latter may appear far anterior to it, posterior, 
or, as in Fig. 8, it may assume an eccentric position and lie on 
the same level; in this case the duct and pore are shown by 
dotted lines, as the pharynx lies about eight sections to the side 
of the median line, z.e., of the genital pore. Thus the new 
pharynx can be found in all possible positions, and the varia- 

Fic. 6. 
Fic. 7. 
Fics. 6, Lm Development of pharynx during presence of reproductive organs. A, penis; B, 
genital chamber ; C, digestive tract (in 6 the wall has broken down — it and the 
degen erating cavity); D, eieo due to degeneration of reproductive organs ; Æ, pharynx ; 
F, pon on oi hn rel 
Fic. 8. 
* 4h 

duct and 
rs to one side of the pore buton the same level. The dotted lines itin di direction 
of it ts following sections 
tions, such as lateral, ventral, and oblique, should be noted in 
connection with any hypothesis of the relation of the pharynx 
to the axial gut. 
As regards the process of regeneration in the posterior pieces 
of worms cut behind the genital pore when the reproductive 
organs were believed to be fully developed, the process of 
formation seems identical with that which takes place during 
the absence of these organs. Consequently there is no need 
to describe what takes place. 
I wish to express my indebtedness to Prof. T. H. Morgan, 
under whose direction this work has been done. 
BIOLOGICAL LABORATORY, BRYN MawR COLLEGE. 

