420 THE INFUSORIA 



and remains for a little while free inside a chamber (brood chamber) 

 of the other part or parent, which is provided with arms and is not 

 ciliated. The application of the terms " gemmula " and " parent " 

 to the two parts in this case is clearly appropriate. 



In many species of Ephelota a number (6-16) of gemmulae are 

 formed at the free surface of the disc, and these may be ciliated 

 (Fig. 14), or provided with tentacles and a small special disc of cilia 

 (Fig. 96), when they are set free. Finally, in some species of Acineta 

 and in Ophryodendron, several ciliated buds are formed in a chamber 

 similar to the chamber containing the single bud in Dendrocometes. 



The free-swimming buds of the Acinetaria are frequently called 

 the " embryos," but as this term may lead to a misunderstanding as 

 to their origin, it is better to call them simply buds or " gemmulae." 

 The gemmulae are sometimes oval in shape, as in certain species 

 of Sphaerophrya, Podophrya (Fig. 20), Ephelota, etc. ; spherical, as in 

 certain species of Triclwphrya ; or plano-convex, as in Dendrocometes. 

 As regards the ciliation, they may be holotrichous, as in Tokophrya 

 elongata ; or hypotrichous, as in Hypocoma, Epheloki gemmipara, 

 etc. The form of ciliation which is most commonly met with is that 

 of a broad band or girdle encircling the equator of the gemmula, 

 or two or more narrow bands arranged in a peritrichous manner as 

 in Dendrocometes and Dendrosoma (Figs. 86 and 33). 



The method of feeding of the Acinetaria is remarkable. The 

 suckers have the power of seizing and holding fast Ciliate and other 

 Protozoa of considerable size. This power might be explained on 

 the supposition that they can exert a sucking action, but there can 

 be no doubt that the prey is not only held fast but also stunned 

 or paralysed in some way by the Acinetarian. Very soon after 

 the prey is secured very small globules may be seen passing rapidly 

 down the sucker (or arm) into the cytoplasm of the disc, proving 

 that the paralysis of the prey is quickly followed by the digestion 

 of its protoplasm and its absorption in a liquid form. 



Very little is known about the encystment of the Acinetaria. 

 Some species of Podophrya and Ephelota form cysts which are 

 probably more resistant to unfavourable physical conditions than 

 the active phase of life. Dendrocometes, however, and probably 

 other genera, may be found at all times of the year, and never 

 show any signs of encystment. 



There is considerable difficulty in dividing the Acinetaria into 

 families, as the whole life-history of very few species has yet been 

 worked out. Sand has shown that Podophrya gelatinosa, Buck, passes 

 from the ciliated gemmula into a stage similar to Sphaerophrya, 

 and that from the Sphaerophrya stage it changes into a form like 

 Trichophrya before it assumes the adult Podophrya form. In this 

 stage it may separate from the peduncle, become ciliated again, and 

 then change into a Sphaerophrya and reproduce by fission or develop 



