230 HOMOLOGICAL RELATIONS OF THE 



mentous motile corpuscules, somewhat resem- 

 bling the spermatozoa of animals ( Anther o- 

 zoids, Phytozoa). 



In Phanerogamic plants, secondary cells formed in 

 the anthers, and protruding, through openings 

 in their outer or cellulose coat, tubules which 

 are outgrowths from the inner coat, or rather 

 from the protoplasmic granular matter which 

 the latter encloses (Fomlla in Pollen grains). 

 In the Animal Kingdom, as a general rule, these corpus- 

 cules appear to be developed as the nuclei of secondary- 

 cells (vesicles of evolution), generated in variable numbers 

 within larger parent cells. But in some Chilopoda, Aca- 

 rina, and Entozoa, the wall, as well as the nucleus of the for- 

 mative cells, seem to enter into their constitution ; and in 

 some Nematoid worms, and in Hydrozoa, it is alleged that 

 they are formed directly as primary cells within the sper- 

 matic gland.* 



The spermatozoa are generally motile filaments, often 

 clavate the larger extremity in some cases assuming the 

 character of a distinct " body," rounded or acuminated 

 but in some Crustacea, in Chilopoda, and in Nematoid 



* Huxley's Oceanic Hydrozoa, p. 22. The secondary cells are de- 

 scribed by some as being formed by the breaking up of the large nucleus 

 of the primary cell in a way somewhat similar to the cleavage of the 

 vitellus of the ovum. It cannot be considered absolutely determined that 

 the secondary spherules, within which the spermatozoa originate, are 

 always true cells. See Burnett's note to Siebold's Comp. Anat. Invert., 

 127. <^uatrefages Ann. des Sci. Nat., 4th Ser., II., 152. The develop- 

 ment of the spermatic particles in the higher Crustacea is described by 

 H. Goodsir (Anatomical and Pathological Observations, p. 39), and more 

 fully by Wagner and Leuckhart, as quoted below. According to the latter 

 authors the spermatozoa are formed singly in projections from the 

 primary cell [which may possibly represent the vesicles of evolution]. 

 In the primary cell there is also an obvious nucleus, projecting externally, 

 but it is eventually thrown off, without itself undergoing any farther de- 

 velopment. 



