DESCRIPTION OF THE PLATES. Ill 



b Absorbent cells of the false membrane, with two 

 globular masses derived from the cartilage cor- 

 puscules. 



SECRETING STRUCTURES. 



PLATE 1. Fig. 14. Four secreting cells from the ink bag of Loligo sa- 



gittata. 



Fig. 15. Five cells from the liver of Patella vulgata. In this 

 instance the bile is contained in the cavities of 

 the secondary cells, which constitute the nucleus 

 of the primary cell. 



Fig. 16. Three cells from the kidney of Helix aspersa. The 

 contained secretion is dead white, and presents a 

 chalky appearance. 



Fig. 17. Two cells from the vesicles of the testicle of Squa- 

 lus cornubicus. The contained bundles of sper- 

 matozoa are developed from the nucleus, each 

 spermatozoon being a spiral cell. 



PLATE II. Fig. 1. Five cells from the mamma of the bitch. In 

 addition to their nuclei these cells contain milk 

 globules. 



Fig. 2. A portion of duct from the testicle of Squalus 

 cornubicus. A few nucleated cells, the primary 

 or germinal cells of the future acini are at- 

 tached to its walls. 



Fig. 3. The primary cell of an acinus in a more advanced 

 stage. The nucleus has produced a mass of 

 young cells. The pedicle appears to have been 

 formed by the germinal cell carrying forward 

 the wall of the duct. A diaphragm accordingly 

 presents itself across the neck of the pedicle. 



Fig. 4. A primary cell in a more advanced stage. 



Fig. 5. A primary cell still more advanced. 



Fig. 6. Some of the secondary cells, products of the 



