GENUS AMPHILEPTUS. 525 



tractile vesicle single, spherical, situated near the posterior extremity ; 

 endoplasts two in number, round or ovate ; cuticular cilia disposed in even 

 longitudinal lines. Length of body 1-280" to I-120". 

 Hab. — Pond water and infusions. 



This species corresponds with the TracheUus anas of Ehrenberg, and with the 

 TricJwda anas and T. index of O. F. Miiller. Through the inception of vegetable 

 food-particles it is frequently coloured bright green, examples so tinted representing, 

 probably, the type upon which Ehrenberg conferred the title of Amphileptus viridis. 



Amphileptus vorax, Ehr. sp. 



Body elongate-pyriform or clavate, rounded posteriorly ; the anterior 

 trunk-like portion thick and obtuse, not equalling one-half of the body in 

 length, flexible and curved in various directions ; oral aperture situated 

 towards the centre of the body, and at some little distance from the base of 

 the proboscis ; endoplast single, ovate. Length of body 1-120". 



Hab. — Pond water, among Confervce. 



This species is referred by Ehrenberg to the genus TracheUus. 



Amphileptus moniliger, Ehr. 



Body elongate-ovate, rounded posteriorly ; trunk-like process short ; 

 endoplast ribbon-like or moniliform. Length of body 1-96" to 1-72". 

 Hab. — Fresh water, amongst Lemnce. 



Amphileptus anser, Ehr. Pl. XXVII. Figs. 39 and 40. 



Body elongate-lanceolate, pointed posteriorly ; trunk-like process equal- 

 ling the body in length ; contractile vesicle single, spherical, posteriorly 

 situated ; endoplasts ovate, two in number. Length of body I-120". 



Hab. — Fresh water, among decaying vegetation. 



According to Claparede and Lachmann, the pharynx of this animalcule presents 

 a longitudinally striate aspect, as in Amphileptus gigas. Although it was left 

 undetermined by these authorities whether these apparent striations were due to 

 membranous plications or to the presence of separate rod-like indurations, as in the 

 genus Prorodon and Chilodon, there appears to be but little doubt that the former of 

 these two premises may be accepted as the correct one. 



Amphileptus margaritifer, Ehr. 



Body elongate-fusiform, trunk-like process slender, equalling the body 

 in length ; contractile vesicles numerous, usually disposed in a necklace-like 

 manner along the dorsal border, sometimes a few others scattered irregu- 

 larly throughout the remaining portions of the body ; cuticular cilia fine and 

 inconspicuous. Length 1-72". Hab. — Fresh water. 



Although the numerous contractile vesicles of this species were not recognized 

 as such by Ehrenberg, but are figured and described rather as accessory vacuoles 

 possessing some digestive function, their existence and true nature, as above 

 intimated, has been fully confirmed by the investigations of Claparede and 

 Lachmann. 



