526 ORDER HOLOTRICHA. 



Amphileptus meleagris, Ehr. sp. PL. XXVII. FIGS. 45 AND 46. 



Body lanceolate, compressed ; trunk-like process short and thick, scarcely 

 prominent ; oral aperture situated towards the centre of the body ; con- 

 tractile vesicles numerous, including a row of ten or twelve arranged along 

 the dorsal border ; endoplasts two in number, centrally located. Length 

 of body 1-96" to 1-60". HAB. Fresh water. 



This species is identical with the Trachelius meleagris of Ehrenberg, but not 

 with the Amphileptus meleagris of the same authority, this latter form being referable 

 to the genus Loxophyllum. An interesting phenomenon connected with the life- 

 history of this animalcule is recorded by Claparede and Lachmann. By various 

 previous investigators its occurrence, in association with cyst-like bodies attached 

 to the extremities of the branches of Epistylis plicatilis and other Vorticellidae, had 

 been noted, and by some of these, including notably D' Udekem, it was supposed that 

 the ciliated Amphileptus was a transitional condition of the Peritrichous type. The 

 Genevan authorities quoted have demonstrated, however, that the Amphileptus repairs 

 to the Epistylis colony for the express purpose of satisfying its hunger, and having 

 detached, swallowed, and digested a selected victim, fixes itself to and becomes 

 encysted at the extremity of the vacant stem. From this encystment the animalcule, 

 after a short interval of repose, makes its exit, sometimes in the simple condition 

 under which it entered, but more often in an augmented form, through its having 

 divided by segmentation within the cyst into two or four portions, each of which, 

 while of smaller calibre, corresponds entirely in form and structure with the original 

 single zooid. This interesting observation of Claparede and Lachmann has been 

 confirmed by various recent observers. An instance of an example attacking and 

 devouring a simple Vorticella, and then developing its characteristic cyst upon the 

 extremity of the semi-retracted and spirally curved pedicle of its victim, has been 

 noted by the present author. A Rhizopodal type, Vampyrella gomphonematis, 

 has been lately shown by Professor Haeckel to devour in a somewhat identical 

 fashion the cell-contents of the frustules of a species of Gomphonema, and upon 

 the branching pedicle of which diatom it afterwards affixes itself and becomes 

 encysted. 



Amphileptus longicollis, Ehr. 



Body dilated and rounded posteriorly, attenuate and trunk-like ante- 

 riorly ; the oral aperture situated nearer to the posterior than to the 

 anterior extremity of the body ; a conspicuous border of larger cilia de- 

 veloped on the lower surface of the trunk-like portion ; contractile vesicles 

 numerous, consisting of nine or ten vacuoles arranged in a line along the 

 dorsal border. Length of body 1-120" to 1-96". 



HAB. Pond water, amongst Conferva. 



Amphileptus anaticula, C. & L. 



Body pyriform, widest and subspherical posteriorly, tapering towards 

 the anterior extremity ; the trunk-like process attenuate, equal to one-third 

 of the length of the entire body, covered with longer cilia than those of the 

 general surface ; contractile vesicle single, postero-terminal ; endoplast single, 

 rounded. Length 1-570" to 1-280". 



HAB. Fresh water, among Confervas. 



Except when feeding, the oral aperture of this species appears only as a 

 small depression at the base of the attenuate proboscis ; but in its elasticity and 



