Floscularia.] TH E INFUSORIA. 343 



Genus CXLIII. TUBICOLARIA. The encased wheel 

 Animalcules are destitute of eyes at all ages (?) have a four- 

 lobed rotatory organ, and a gelatinous case (urceolus). 

 Their internal structure comprises four posterior longitudi- 

 nal muscles, an alimentary canal, with a long stomach, 

 devoid of coecal appendages ; a short rectum, an oesophagal 

 head with four muscles, two jaws with teeth, two semi- 

 spherical pancreatic glands, and an ovarium,with a single 

 ovum. Anteriorly, upon the ventral surface, are two res- 

 piratory tubes. 



574. TUBICOLABIA najas. The mantle Tubicolaria. 

 The jaws have four teeth, and the respiratory tubes are 

 hairy anteriorly. It is described fully in the account of 

 the genus, and figures 379 to 382 will illustrate it ; 381 

 represents those of the natural size, as found attached to 

 the roots of Lemna polyrrhiza, with those of the following 

 genus ; 379 represents an animalcule within its case, the 

 rotatory organ withdrawn ; 380, another animalcule ex- 

 tended, and without its lorica. Fig. 382 shews the oeso- 

 phagus, with the jaws and teeth separate. Length 1-3 6th. 



Genus CXLIV. STEPHANOCEUOS. The crown-wheel 

 Animalcules have one eye, and a rotatory organ, deeply 

 divided into lobes, and furnished with verticellate cilii : 

 this organ performs the office of locomotion. Their nu- 

 tritive apparatus consists of a simple alimentary canal, 

 with a stomach, and small rectum ; the oesophagal head 

 has jaws, with free teeth, four in number ; before it is a 

 large crop-like structure, and two glands at the stomach ; 

 the ovarium only developes a few ova at a time ; perhaps 

 two male glands exist at the commencement of the row of 

 tremulous gills ; a red visual point, with a row of nervous 



