FLORIDE.-E 



199 



duced, like the tetraspores, in wart-like protuberances or neijiaiheces on the 

 surface of the thallus, and interspersed with paraphyses, sometimes 

 (Gracilaria, Grev.) in depressions which are overarched by the surround- 

 ing tissue ; or. in the Corallinace^, in special conceptacles. When the 

 thallus is otherwise unilamellar, as in Porphyra (Ag.), the spots where the 

 antherids are formed divide by walls parallel to the surface. The fer- 

 tilising bodies ox pollmoids are naked masses of protoplasm, of a spheri- 

 cal or elongated form, sometimes with a beak-like appendage, and are 

 discharged in succession one after another. They are carried along 

 passively by the water, and are distinguished from the antherozoids of 

 other Cryptogams by the absence of cilia, and, in most cases, of any 

 spontaneous power of motion. Wright (Trans. Irish Acad., 1879, P- ^7) 



Fig. 176. — Sperviothamnion Jiennaphrodifuvi (magnified). A , branch with procarp 

 {tyg i) and antherid {an) before fertilisation ; B, after fertilisation, the cystocarp 

 developing ; t, trichogj-ne ; c, trichophore ; g, carpogenous cells. (After Nageli.) 



states that in Griffithsia (Ag.) the pollinoids have an obscure amoeboid 

 motion, as they have also in the Porphyraceas ; according to Dodel-Port 

 their access to the trichogyne is greatly facilitated by the currents made 

 in the water by Vorticellse and other Infusoria ; and there can be little 

 doubt that fishes which feed on seaweeds are an important agent in pro- 

 moting their fertilisation. The pollinoids and the tetraspores appear to 

 be homologous in their origin. 



The female organ before fertilisation — corresponding functionally 

 to the pistil of Flowering Plants — is termed \hc procarp. In its simplest 

 form (PorphyracejE and Xemalie^) it consists of a single cell with a 

 lateral hair-like prolongation, the trichogyne. But in all the higher 

 forms the procarp is composed of one or more fertile cells constituting 

 the carpogone, and one or more infertile cells which make up the tricho- 



