EXPLANATION OF PLATE 7. 



Fig. 1. Gravid uterus of Pteroplatcea micrura, opened by a 1 longitudinal incision im 

 its dorsal wall, with, the flaps turned back, so as to show the passage of the- 

 large bundles of trophonemata through the spiracles into the pharyngeaL 

 cavity of a single foetus. 



Fig. 2. Head and shoulders of the same foetus from the left side,, to- show the great 

 size and the lateral position of the spiracles. 





