GAMETOGENESIS AND SPOROGENESIS 225 



tives.-^ In ciliated epithelial cells, according to Saguchi, there is a basal 

 corpuscle at the base of each cilium. The granules and cilia are in parallel 

 rows. Beneath each row there is a transparent zone in which the rootlets 

 of the cilia are anchored and through which they pass and become 

 continuous with strands of a cytoplasmic reticulum. Saguchi regarded 

 the basal corpuscle as the kinetic center of ciliary movement but not as a 

 centriole derivative. 



In the gill cells of certain mollusks^" the ciliary rootlets below the 

 basal corpuscles form a continuous system which probably represents the 

 structural basis for the coordinated action of the cilia of a given cell. 

 The view of Grave and Schmitt, that the systems of adjacent cells are 

 continuous, is disputed by Bhatia and by Lucas, who believe the coordi- 

 nating impulses pass from cell to cell through the general cytoplasm and 

 the membranes. In any event, the evidence shows clearly that the cilium 

 or the flagellum is itself an actively contractile element and not merely a 

 passive element operated by an intracellular mechanism (see Gray, 1931). 



-^ Henneguy (1897), Lenhossek (1898). This theory is favored by Helvestine 

 (1921), Jordan and Helvestine (1923) for certain cells, and Kindred (1927). It was 

 opposed by Saguchi (1917) and by Erhard (1911), who reviewed the evidence then 

 available. 



^0 Grave and Schmitt (1924, 1925) on Lampsilis and Quadrula, Bhatia (1927) on 

 Mytilus, Lucas (1931) on Mytilus and other genera. 



