Bacillaria.] THE INFUSORIA. 229 



the form of a fan, or cluster-like. The chief character of 

 the genus, however, consists in the fact of the self-division 

 not influencing the division of the stalk, for the body 

 often divides again without the stalk taking part in the 

 division. During the division of the body, that of the 

 stalk often rests quiet, either periodically, or for ever. 

 Young forms of Echinella are with difficulty distinguished 

 from species of Gomphonema, and stalkless ones from 

 those of Synedra, to which latter their organization closely 

 approaches. 



323. Echinella flabellata [Exilaria, Greville). The 

 fan-shaped Echinella is smooth and shrub-like ; the lorica 



is in the form of a truncated wedge, obtusely tridentated, 

 and longitudinally striated. They are attached by the 

 smaller ends to a stalk, and disposed in a fan-like group. 

 This pretty animalcule covers various marine plants or 

 Algae, as shewn (of the real size) in fig. 191 ; they appear 

 of a golden colour. The thick tender gelatinous branched 

 stalks resemble those of the Vorticella. (See the tree- 

 like group 192.) The stem is an excretion produced by 

 the animalcule, probably like the shells of the Molusca, 

 and, like them, is devoid of organic or vital power, and if 

 the fan -shaped bodies separate from it, does not evolve 

 new bodies in the form of gemmae, but disappears. 

 Group 193 shews a dorsal and lateral view of a single 

 animalcule. Length, without stalk, l-120th; height of 

 tree, 1-1 2th to l-6th. 



324. Echinella splendida. The beautiful Echinella is 

 smooth, and branched ; the lorica is rather straight or 

 club-shaped, with rounded ends; they are dispersed 

 or arranged in fan-hke clusters, at the swollen extre- 



