280 ANATOMY AND PHYSIOLOGY 



FIG. 



317. An ovariumof Spongillajluviatilisw its natural state, 



exhibiting the foramen. X S3 linear. Page 

 132. 



318. A perfect skeleton of an ovarium of Spongilla fluma- 



tilis, Johnston, prepared with nitric acid. X 183 

 linear. Pages 60 and 136. 



319. View of a section, at right angles to the surface, of a 



fragment of the skeleton of the ovarium of Spon- 



gilla fuviatilis, prepared with nitric acid, exhibiting 



the relative positions of the spicula in the skeleton. 



(a) A spiculum detached from the same ovarium 



X 308 linear. Pages 60 and 136. 



320. A skeleton of an ovarium of Spongttla lacusfris, pre- 



pared with nitric acid, exhibiting the spicula in 

 situ and the foramen. X 183 linear. Pages 58, 

 60 and 137. 



321. Two of the reticulated cases of the ovaria of Spongilla 



Brownii, Bowerbank : a, an empty case ; b, a 

 case containing the skeleton of an ovarium. X 50 

 linear. Page 139. 



3*22. A reticulated case of an ovarium of SpongiUa reticu- 

 lata, Bowerbank. X 175 linear. Page 138. 



323. Skeleton of an ovarium of Spongilla reticulata, 



Bowerbank, without its case, prepared with nitric 

 acid. X 175 linear. Page 138. 



324. A perfect ovarium of Diplodemia vesicula, Bower- 



bank, and a portion of a second one, showing the 

 interior and the thickness of its walls in its 

 natural state. X 83 linear. Pages 60 and 140. 



325. An ovarium of GeodiaMcAndrcwii, Bowerbank, MS., 



in very nearly an adult state, showing the struc- 

 ture and position of the conical foramen for the 

 discharge of the ova, natural condition. X 183 

 linear. Page 142. 



