DesmidiecB.'] infusorial animalcules. 2<5D 



Staurastrum echinatam (Breb.) — "Appears, from. M. de Biebisson's 

 drawings, to be closely allied to S. hirsutum, and S. teliferum.'" 



S. crenatum (Bailey) — Segments cnneate ; outer margins crenate ; 

 end view with tlu-ee truncate and crenate angles. 



S. hifidum. = Desmidiiim hifidum (Ehr.) — Smooth ; end view with 

 thi'ee cloven angles. 



S. eiistcj)Jianui>i. = Desmidiiim eustephanum (Ehi-.) — End view tri- 

 angular, with six emarginate spines on the upper surface; each 

 angle terminated by a short ray, tipped with spines. (P. 13. f. 3.) 



S. senarium. = Desmidium senarium (Ehi*.) — Ehreuberg's figure 

 represents the end view as triangular, the angles terminating in short 

 rays, tipped by minute spines ; on each side are two short forked 

 spines, and six others on the upper surface. His figure agrees in 

 some respects with S. spinosum. (P. 13. f. 7.) 



S. Ehrenbergii (Corda.) — Segments oval ; end view triangular, 

 with six terminal and lateral processes, and two centi'al ones, which 

 are short, colouiiess, and forked, with diverging apices. Corda's 

 figure of the ffont view resembles S. spinosum. 



S. articulatum (Corda.) — Seg-ments oval, their ends furnished with 

 a forked process, and laterally with two larger furcate appendices. 

 The flat surface has two transverse protuberances, with forked spines. 



S. coronatum = Xanthidium coronatum (Ehi-.) — End view tri- 

 angular, and terminating at each angle in three short, diverging 

 arms, which are divided at the apex. 



S. (?) minus (Kiitzing.) — Smooth; end view with five slender 

 acute rays. 



S. glabncm = Desmidium glahrum (Elu\) — Smooth; end view tri- 

 angular, each angle terminated by a mucro-like spine. This species 

 is probably identical with S. auricula. 



S. granulosum = Desmidium granulosum (Ehr.) — Known only by 

 name to Mr. Ealfs. 



S. ghhuJatum. — Segments fusiform, capitate; end Adew globular, 

 each angle terminated by a granulated knob. 



Genus Pesxasterias (Ehr.) — The five-rayed Desmidiecn. — Lorica 

 simple, univalve, five-sided, with a central aperture ; free, but some- 

 times developed in chains. 



This genus, instituted by Elu-enberg, contained, in 1838, but one 

 species, called P. margaritacea, the Staurasirum tnargaritaceum (Ralfs), 



