Mycetomorpba. 



587 



and larg-ely in the form of o-iobules about the same size as tlie 

 nuclei. Great masses of the same material have been exuded 

 into the cavity of the ovary, occupying the Spaces between the 

 ovariaii follicles. Here the substance has a homog-eneous granulär 

 appearance, the globales having disappeared. There is a general 

 similarity to the yolk which is formed round the periphery of the 

 developing eggs. 



It is not certain 

 how far the meso- 

 dermal epithelium of 

 the ovarian cavity 

 participates in the 

 production of this se- 

 cretion. xis may be 

 Seen in the section 

 drawn here (PL 16, 

 Fig. 11) these epi- 

 thelial cells become 

 larger in the neig- 

 bourhood of the glands 

 and contain the gra- 

 nulär substance, but in the middle of the area they appear to be 

 absent. In other sections a proliferation of these mesodermal cells 

 is Seen, which may, however, play an important part in secretion. 

 The muscular layer appears to be suppressed throughout the region. 

 The increased activity of the ectodel cells is also shown by the 

 great thickness of the chitinous cuticle (cJi) over the glands. 



It has been pointed out to me by Mr. Geoffkey Smith that 

 these glands are probably homologous with the colleterial 

 glands of the form described by him as Duplorlns and provisionally 

 assigned to the Rhizocephala. These are disc-shaped organs which 

 are developed from the ectoderm of the viscei-al mass and consist 

 of columnar epithelial cells. If they represent the colleterial glands 

 of typical Rhizocephala, their structnre is mucli simplified. Nothing 

 is known about the manner in which they function. 



The colleterial glands in those forms where their structure and 

 function are best known, Sacculina and Peltogaster, are tubulär 

 structures which form part of the female ducts, and they secrete 

 a mucilaginous substance which binds the eggs together when they 

 are forced out of the ovaiy into the ducts. When these masses of 



39* 



Fig-. K. Transverse section throngh body in the 

 region of the ectodernial glands (gl) of the visceral 

 mass. (Other abbreviations as in preceding fignres.) 



