6 7 2 



THE GENERATIVE ORGANS. 



their widest part. The azygos oviduct in the same condition 

 is about 2 mm. in length, and is nearly i mm. in breadth when 

 seen flattened out after dissection. During the transit of the 

 ova the oviducts become greatly elongated ; the tubae usually 

 each contain an ovum, whilst the azygos oviduct often contains 



A 



B. 



FIG. 94. Transverse sections of the parovaria of the Blow-fly. A, section 

 through a mature parovarium ; B, a single cell from the same, showing 

 the included corpuscle, the germ ovum, and the nucleus ; C, a section of the 

 parovarium in a less developed condition ; D, a section showing the adjacent 

 fat body ; , section through an immature parovarium. All the figures except 

 /> represent the structures as they appear with a ,'.. oil-immersion objective. 

 f, fat-cells ; , nuclei ; o, germ ovum ; v, vitellme vesicle ; c, zona radiata. 



two or three, so that the whole length of the tube must exceed 

 4 mm. And sections show that its course is exceedingly tor- 

 tuous. The ducts of the }>art>v;iriu open into the anterior 

 part of the sacculus. 



The Parovaria. The glands which I term parovaria in the 

 Blow-fly arc simple tortuous, rather than convoluted, tubes, 



