Bacillaria.] THE INFUSORIA. 227 



smooth. Found, fossil, in the Schistus of Bilen. Length 

 1 -2300th to 1-1 720th. 



Genus LXVIII GOMPHONEMA. The wedge little tree 

 Animalcules. These Infusoria have a simple siliceous 

 lorica, are fixed upon a distinct filiform pedicle, and 

 develope themselves, by spontaneous self- division, in the 

 form of a dichotomous little tree. The lorica is wedge- 

 shaped, composed of from two to four pieces. At the 

 broad anterior end are two openings, and one in the 

 centre of the dorsal and ventral surfaces. The stalk is 

 an excreted, immovable, horny substance ; at its attach- 

 ment to the lorica there is no opening in the latter ; the 

 animalcule can detach itself, creep about independently, 

 and probably form another stalk. In some instances the 

 lorica appears to be transversely striated internally. 



314. GOMPHONEMA truncatum (Vorticella pyraria, M.) 

 The truncated Gomphonema is striated. In the engraving, 

 group 187* and jigs. 188 to 190, represent various views 

 of this creature, both separate and attached; these will 

 convey a far better idea of their form, and the mode of 

 attachment of the genus, than any verbal description. 

 Separated animalcules move distinctly. Found free in 

 water and upon lemna, &c. Fossil in Franzenbad and 

 Santi Fiora. Length l-l?20th to l-280th. 



315. GOMPHONEMA capitatum. The round-headed Gom- 

 phonema is striated, has an elongated cuneiform-shaped 



lorica, laterally constricted near the rounded end. Length 

 l-!720th to l-280th. 



316. GOMPHONEMA gracile. The slender Gomphonema 

 is smooth ? the lorica elongated and wedge-shaped. This 

 species, and the preceding, form a brownish-yellow slime 



Q 2 



