Chapter 36 

 Order 1 Holotricha Stein (continued) 



Suborder 6 Apostomea Chatton et Lwoff 



ASYMMETRICAL forms with a rosette-like cytostome 

 ^ through which hquid or small solid particles are taken into 

 the body; sparse ciHary rows spiral; adoral rows short; macronu- 

 cleus oval to band-form; a micronucleus; a single contractile 

 vacuole. 



The life-cycle of the ciliates grouped here appears to be highly 

 complex and Chatton and Lwoff (1935) distinguished several 

 developmental phases (Fig. 257), as follows: 1) Trophont or vege- 

 tative phase: right-spiral ciliary rows; nucleus pushed aside by 

 food bodies; body grows, but does not divide. 2) Protomont: 

 transitory stage between 1 and 3 in which the organism does not 

 nourish itself, but produces "vitelloid" reserve plates; nucleus 

 central, condensed; ciliary rows become straight. 3) Tomont: 

 the body undergoes division usually in encysted condition into 

 more or less a large number of small ciliated individuals. 4) Pro- 

 tomite: a stage in which a renewed torsion begins, and which 

 leads to tomite stage. 5) Tomite: small free-swimming and non- 

 feeding stage, but serves for distribution. 6) Phoront: a stage 

 which is produced by a tomite when it becomes attached to a 

 crustacean and encysts; within the cyst a complete transforma- 

 tion to trophont takes place. 



Family Foettingeriidae Chatton 



Genus Foettingeria Caullery et Mesnil. Trophonts large, up to 

 1 mm. long; sublenticular, anterior end attenuated; dorsal sur- 

 face convex, ventral surface concave; right side less convex than 

 left side; 9 spiral ciliary rows nearly evenly arranged; in gastro- 

 vascular cavity of various actinozonas; tomont on outer surface 

 of host body, gives rise to numerous tomites with meridional 

 ciliary rows; each tomite becomes a phoront by encysting on a 

 crustacean, and develops into a trophont when taken into gastro- 

 vascular cavity of an actinozoan. One species. 



F. actiniarum (Claparede) (Fig. 258, a). Phoronts on Copepoda, 

 Ostracoda, Amphipoda, Isopoda and Decapoda; trophonts in 



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