GENUS HETEROMITA. 295 



of solid food-particles at any point been directly observed, testimony to this effect 

 would undoubtedly have been placed on record. Since, however, both in their 

 illustrations and descriptive text all evidence of food-ingestion or of a food-ingesting 

 aperture is conspicuous for its absence, there is substantial ground for premising 

 that these lowly organized beings derive their sustenance after the manner of the 

 OpaUnida^, by the direct imbibition, at all parts of their periphery, of the proteaceous 

 nutritive fluids within which they are constantly immersed. 



Heteromita ovata, Duj. Pl. XV. Figs. 65 and 66. 



Body ovate, narrower anteriorly ; surface smooth ; endoplasm slightly 

 granulate ; anterior or terminative flagellum slender, two or three times 

 longer than body, flexible throughout; posterior or anchoring flagellum four 

 times the length of the body, and twice the thickness of the anterior 

 one ; contractile vesicle conspicuous, situated near the anterior extremity. 

 Length of body i-iooo" to 1-700". 



Hab. — River water with aquatic plants. 



A form agreeing structurally with the terms of the foregoing diagnosis has been 

 met with by the author in pond water, its increase by longitudinal fission, and the 

 inception of food at various points of the periphery being also observed. 



An animalcule presumed to be identical with this species but having a depressed 

 lenticular contour with a plane ventral and convex dorsal surface, is figured by 

 Stein under the name of Bodo ovatiis, his drawings of it being represented in 

 the accompanying plate. As there indicated, no less than three minute spheroidal 

 contractile vesicles are stationed at the anterior extremity, the endoplast being 

 located close behind them in the middle line. The two flagella as deUneated by 

 Stein are very slender and subequal in both length and thickness. 



Heteromita globosa, Stein sp. Pl. XV. Figs. 61-64. 



Body somewhat variable in shape, more usually subspheroidal or 

 elliptical, surface coarsely granulate ; flagella slender, subequal in length 

 and thickness, two or three times the length of the body, inserted ventrally ; 

 contractile vesicle single, situated close to the centre of the right lateral 

 border ; endoplast spherical, located in the median line towards the anterior 

 extremity. Length of body 1-2500" to i-iooo". 



Hab. — Pond water. 



This species is figured by Stein * in association with the tide of Bodo globosus. 

 An apparently identical form has been recently met with by the author in pond 

 water from the neighbourhood of Birmingham, remitted by Mr. Levick. Numbers 

 were crowded together within the carapace of a dead rotifer, Noteus, feasting upon 

 its contents under conditions analogous to those reproduced from Stein's drawings 

 at Pl. XV. Fig. 64, the pabulum in this instance being however the cell-contents 

 of a fragment of (Edogo>iii/?n. When thus collected within a small space, the dis- 

 tinction between the vibratile and trailing flagellum is not apparent, both appendages 

 being deployed in advance and exhibiting an irregular undulatory modon. Except 

 for their larger size and coarse granulation, the animalcules of this species coincide 

 considerably in general form and proportions with those of Heteromita lens. The 

 contractile vesicle, among other points of distinction, may be cited, however, as 

 occupying a more anterior position. 



' Infusionsthiere,' Abth. iii., i{ 



