160 CONJUGATED. 



11. TYNDARIDEA Bory. 



Char. Endochrome disposed in the cells in a star-like form, 

 the stellate masses being double in each cell. Sporangia 

 usually circular, sometimes lodged in the cells, and occa- 

 sionally in the connecting tubes. 



Derivation. Tyndaridce, the constellation so called of Cas- 

 tor and Pollux ; in allusion to the twin star-like masses 

 contained in each joint. 



Stellulina Link, Handb. iii. 261. Agardhia Gray. Glo- 

 bulina Link, in Hor. Physic. 5. Lucernaria Rouss. 

 et Desv., Jour. Bot. i. 143. Tyndaridea et Led<B species 

 Bory, in Diet. Class. Conjugates, sect. 11. Vauch. pi. 6, 7. 



The species of the genus Tyndaridea are distinguished by 

 the arrangement of the endochrome, which is in star-like 

 masses, two of which are contained in each cell, connected usu- 

 ally by a band or tube. Concerning the nature of these bodies, 

 numerous conjectures have been hazarded. It has been sup- 

 posed that the one represented the male and the other the 

 female, the sporangia resulting from their union : this con- 

 jecture, however, does not seem probable. This form, as well 

 as the beautifully spiral arrangement of the endochrome, in 

 the genus Zygnema, has doubtless been impressed upon these 

 plants by the Deity, in order that they might appear the 

 more attractive and more wonderful in the eyes of man. 



The sporangia are usually circular, and lodged either in 

 the cells themselves, or in the transverse tubes. By this dif- 

 ference in the situation of the sporangia, the genus admits of 

 a natural division into two subgenera. 



First Subgenus. Sporangia placed in the cells of one or other 



filament. 



1. TYNDARIDEA CRUCIATA Hass. 

 Plate XXXVIII. Fig. 1. 



Char. Filaments of considerable size. Cells once or once and 

 a half as long as broad, at first densely filled with en- 



