77 



NOTE ON 'ACINETA FORMS/ 



It seems proper to conclude, with Lachmann, that 

 these organisms are not, as was formerly supposed, 

 Rhizopods allied to Actinophrys, nor yet again meta- 

 morphosed conditions of Vorticellcs, but that they 

 rather constitute a distinct group of Infusoria, to 

 which the term 'polystome' might, without objection, 

 be perhaps applied. For each of the radiating fila- 

 ments {fig. 15, e) with which the AciiiefcB are pro- 

 vided is, in truth, a retractile tube, susceptible of 

 elongation to a remarkable extent, and furnished at 

 its extremity with an adherent disk. With the aid 

 of these unique organs an Acineta is enabled, not 

 only to seize and retain its more active prey, but also 

 to imbibe the nutrient particles contained in the body 

 of the latter, by a peculiar method of suction. ^Tien 

 the size of the prey is considerable, this process has 

 been observed to occupy several hours. With the 

 exception of the above-mentioned mouths, no other 

 aperture has been hitherto discovered in the bodies 

 of these animals. 



