l86 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



between the epithelial cells. These glandular cells bear a 

 strong resemblance to the tubercula pubertatis cells described 

 from Dichogaster Crawi, but they have the peculiarity of 

 opening into a chamber surrounding the apex of the seta. 

 This chamber opens to the exterior through the setal 

 external pore, which, as before stated, is surrounded by a 

 slightly elevated ring. Thus the glandular cells extend 

 from the various ventral parts of the somite, their ducts 

 leading to this pore. The distal ends of the cells are all 

 bent upwards or downwards, but the long narrow ducts run 

 parallel and close together until they reach the pore. The 

 secretion in these cells stains but faintly, and in this respect 

 resembles that of the tubercula pubertatis. Figure 154 

 represents a longitudinal section of this glandular zone. 

 The seta comes in from above, but has been cut off 

 obliquely. The chamber into which the glands open is 

 furnished with side pockets into which some of the glandular 

 cells open. The walls of all the cells are very distinct. 

 The coelomic epithelium in somites VIII, IX and X is 

 granular and resembles chloragogen cells. The cell-con- 

 tents consists of small and numerous round, dark-staining 

 granules. The cells themselves are of different sizes, 

 protruding more or less freely and independently into the 

 coelomic cavity, while their thin ends lose themselves 

 among the muscular layers. 



Another interesting feature of this glandular structure 

 is a double row of cells as in a prostate. The long 

 glandular cells may readily be compared to and are perhaps 

 homologous with the long glandular cells of a common 

 prostate, while the narrow cells lining the chamber into 

 which the former cells open are similar to the inner layer of 

 cells of the prostate. If the whole structure had been free 

 in the ccelom instead of being enclosed by the layers of the 

 body-wall, its similarity to a prostate would have been 

 almost complete. This fact gives great probability to the 

 opinion of Michaelsen, that the prostates are differentiated 

 cell-structures originally connected with setae. 



J 



