852 



mi. WILLIAM NICOLL ON 



uneqiial contraction of the pharyngeal walls or perhaps due to the 

 drawino- of the a^sophagus into the lumen of the pharynx, but 

 neither" of these possibilities seemed to accord with experience. 

 The condition appears to be brought about by the thinning ot the 



Text-fig. 122. 





-c. 



A B 



M. Khodes del. 



A. SfypJilodora najce, sp. n. Ventral view, x 40. C, cirrus ; 

 Ov., ovaiy; B.S., receptaculum semiuis. 



B. Xenophari/nx solus, gen. et sp. n. Ventral view, x 25. 

 Ov., ovary. 



posterior part of the pharyngeal wall, which anteriorly is of the 

 usual thickness. In section the appearance is somewhat horse- 

 shoe-shaped. It is unfortunate that no second specimen was 



