56 



MORPHOLOGY 



Nemalion. — This marine form will serve to illustrate the simpler 

 red algae. It is a branching filament, and probably produces no tetra- 

 spores. 



Anlheridia. — The antheridia occur in clusters at the ends of short 

 branches (fig. 146), each antheridium being a single cell, which at first 

 contains a single nucleus. This nucleus divides, so that the protoplast 

 of the mature antheridium contains two male nuclei. Physiologically, 



therefore, the an- 

 theridium contains 

 two sperms, but 

 they are not organ- 

 ized as morpho- 

 logically distinct 

 sperms. This bi- 

 nucleate protoplast 

 is discharged from 

 the antheridium, 

 and not being cili- 

 ate it is carried by 

 water currents to 

 the female _ organ. 

 This non-motile 

 sperm, or sperm 

 complex, is usually 

 called a sperma- 

 tium, but there is 



Figs. 146-148. — Nemalion : 146, branch showing antheridia no special ad van- 

 forming at the tips; 147, the procarp, consisting of trichogyne fg^gg jjj multiolvinff 

 and carpogoniura (in the latter the male and female nuclei are 



observed, the former having passed in from the trichogyne); '•"^ names 01 a 

 also shov»ing two other cells with the broad cytoplasmic con- male cell. The 

 nectidns; 148, a cystocarp, showing the carpospores being cut cr^ppjol name was 

 off at the tips of short branches, which have arisen from the 



fertilized carpogonium. felt to be necessary 



when motile sperms 

 were called spermatozoids or antherozotds, but the general term sperm 

 can be applied to non-motile as well as to motile male cells. 



Female sex organ. — The female sex organ of Nemalion illustrates, 

 perhaps in its simplest form, this remarkable structure among the red 

 algae, which usually consists of several cells and is called the procarp. 

 In Nemalion the procarp consists of what may be regarded as two cells 



