534 W. B. HAEDY. 



integration of the sphere approaches completion, the vacuole 

 in which it lay becomes obliterated ; or they may be rapidly 

 and entirely dissolved and discharged from the cells, the 

 vacuoles meanwhile persisting and leaving the striking honey- 

 combed appearance described above (fig. 22). Whatever may 

 happen to the constituents of the sphere in the first case, 

 which agrees with the fate of the nutritive spheres of Hydra 

 as described by Kleinenberg and Greenwood, we can only con- 

 clude that in the second case they have been dissolved and 

 discharged into the enteric cavity. It is even possible that we 

 may divide the endoderm-cells, other than the gland-cells, into 

 two sets: (1) Those which are concerned in the elimination 

 of waste matter from the nutritive spheres or from the somatic 

 fluid directly. These are the apical cells of the villi and the 

 vacuolate cells in their immediate neighbourhood. And (2) 

 Those which discharge their stored material, leaving, so far as 

 can be detected, no residue. These lie towards and between 

 the bases of the villi in the blastostyles and middle regions of 

 the body and foot. 



This conclusion, which may be accepted as a provisional 

 hypothesis until the processes taking place in the endoderm 

 shall have been worked out more fully, is based upon two facts ; 

 namely, that the pigment, as was noted by AUmann, is located 

 only in the cells near the free ends of the villi, and that the 

 bubbly cells in all their various conditions of incomplete or 

 complete discharge always lie between or towards the bases of 

 the villi. 



Another point of evidence in favour of the view that the 

 somatic fluid conveys stored nutriment from one part of the 

 body to another is derived from a study of the histology of the 

 spadix of the gonophores. 



Structure of the Spadix of a Gonophore. — This, 

 in the completely formed female gonophore, is composed of 

 a considerable number of tongue-shaped villi, which have their 

 apices turned towards the axis of the spadix, and project 

 a considerable distance downwards towards the centre of 

 the blastostyle. The cells between their bases, and therefore 



