Peridinaea.l infusorial animalcttles. 515 



In smmniing it revolves upon the longitudinal axis ; this motion is 

 probably produced by a delicate filiform proboscis, or by cilia at its 

 mouth, but though evident, the organs producing it have not been 

 seen. Of the nutritive, sensitive systems, &c., nothing positive is 

 known. One species has been discovered in flint, which so closely 

 resembles Xanthidium, that it is often mistaken for it. 



Chaetottphla artnata. — Is of a brown colour, ellipsoidal form, with 

 roimded ends ; the posterior is covered "with short spines, and has a 

 cii'clet of black spots, as shewn in the end view, fig. 215. The anterior 

 cilia or fine bristles, are sometimes veiy indistinct ; fig. 214 is a 

 variety in which they are strongly marked. Found in clear water, 

 amongst Conferva. Length 1 -620th. 



C. aspera. — Is brown ; body oblong, rounded at both ends, and 

 rough, with short bristles ; the little spines are scattered without 

 order at the posterior end. Found with the preceding. Length 

 l-570th. 



C. (?) pt/ritae.— Body oblong cylindrical, rounded at both ends, and 

 provided with deKcate elongated bristles, but destitute of spines. 

 Found fossil, in flint, near Delitzsch. Size 1-11 50th. 



Genus Chaetoglena. — The bristled and eyed Atiimalcules have a 

 siliceous lorica, striped or covered with spines or stiff hairs, and an eye; 

 they are destitute of a transverse zone or furrow. The organ of loco- 

 motion is a simple flabelliform proboscis. The interior contains 

 scattered transparent vesicles, probably stomach-cells. The ova 

 cluster is a brownish-green granular mass ; a large bright spot or 

 spennatic gland is also visible. Self-division has not been observed. 



C. volvocina. — Body ovate, with brownish-green oval and a red 

 eye ; between the lorica aud the soft body a beautiful red ring is 

 visible in the live specimens. (See fig. 216, 217, and 218.) Found 

 amongst Conferva, at Hampstead and Hackney. Length 1-11 50th. 



C. caudata. — Body hispid, ovate, with a short tail ; ovules green ; 

 oceUus (eye) clear red ; oral margin urceolate and dentate. Size 

 l-864th. Berlin. 



Genus Pekemnifm. The wreath Animalcules.— Lovica membranous, 

 with a transverse ciliated zone ; no eye. The locomotive organs are 

 a filiform proboscis, and the zone or wreath of cilia. In P. pulvlsculiis 



