590 DESCiiipriON OF {Toli/gastrica. 



drical, rounded auteriorly, attenuated posteriorly, forming a straight 

 long tail. It is considered a Spirostomum by Dujardin. Found in 

 stagnant spring water, &c. Size l-48th. 



Genus Ophryoglena derives its name from the animalcules 

 possessing an eye auteriorly, and having a ciliated ovoid body. 

 Locomotion is effected by numerous regular longitudinal series of 

 cilia. The numerous digestive cells are often filled with Naviculse, 

 and in one species they have been demonstrated by indigo. The 

 mouth is situated in a cavity beneath the brow to one side, and the 

 discharging orifice upon the dorsal surface, at the base of the little 

 tail. The ova granules are brown in one species, black in another, 

 and yellow in the third. A large central gland exists in one 

 species, and contractile sexual vesicles in the others ; transverse 

 and longitudinal self-division has been observed in one species. 

 A system of sensation is indicated by the presence of a large 

 red or black visual organ, always pi-esent on the frontal region. 

 These Infusoria are found in stagnant fresh water, but not in 

 infusions. 



0. atra {Leucophra mamilla, M.) — Body blackish, ovoid, com- 

 pressed, acute posteriorly. The cilia are white, the eye black, and 

 situated near the frontal dorsal margin. The mouth aperture 

 forms a funnel shaped cavity, commencing immediately beneath 

 the brow ; within this cavity Ehrenberg thinks he has lately seen 

 an oval bright gland. The white cilia appear like silver fringe, 

 especially those in front. Found in turf hollows. Size l-180th. 



0. acuminata. — Body brown-coloured, ovate, and compressed; 

 tail short and acute; eye red. The brow projects beyond the 

 mouth about the length of the body, or, in other words, is situated 

 about the middle. Figs. .'334, 335, are two views of the same animal- 

 cule. Found in turf hollows. Size l-180th. 



0. Jiucicans. — Body yellow, turgid, ovate, attenuated and rounded 

 posteriorly, eye red ; the cilia near the mouth longer than in the 

 preceding species ; Ehrenberg counted from twelve to sixteen rows 

 at one view. Found in turf hollows. Size l-144th. 



The additional genera to be here added from Dujardin are, 

 Dileptus and Loxophyllum. 



Genus Dileptus. — This genus belongs to the family 'Tricho- 



