376 Ciliophora 



at the end of a groove, in a small depression next to the rosette, and opens 

 into a canal which leads inward, along the concave wall ("typhlosole") 

 of the rosette, to an "oral pouch." The rosette contains 8-10 vertical septa 

 which join the outer wall to the "typhlosole," and the base of the typhlo- 

 sole is equipped with a ring of cilia (Fig. 7. 25, C). De Morgan (45) 

 never observed movement of the rosette in living F. octiyioriiim and ob- 

 tained no clvies in regard to its functions. There are fewer than 22 com- 

 plete rows of somatic cilia but their exact number and the organization 

 of the adoral ciliature vary in different genera. 



A complex life-cycle is characteristic (28, 1,H5). In the growth-stage, or 

 "trophonte" (Fig. 7. 25, F, J, L), food is ingested and accumulated during 

 growth but there is no reproduction. At maturity, the "trophonte" stops 

 feeding, and with or without encystment in different species, becomes 

 transformed into a "protomonte." If the "protomonte" is an encysted 

 stage, the cilia are discarded. The "protomonte" develops into a "to- 

 monte" in which the accumulated food is transformed into stored reserves. 

 Then repeated fission occurs to produce many small "protomites" (Fig. 

 7. 25, M), each of which becomes an actively swimming "tomite" (Fig. 7. 

 25, E, G, I). This migratory stage becomes attached to the body of a host, 

 usually a crustacean. However, Chromidina elegans has been reported 

 from the kidney of a cephalopod (222). After attachment, the "tomite" 

 develops into a resting cyst, or "phoronte" (Fig. 7. 25, K). When the host 

 is ingested by a coelenterate or a ctenophore, or when the host molts, a 

 young "trophonte" emerges from the cyst. The vegetative stage ("tropho- 

 tomonte") of Chromidina elegans is unusual in that it may undergo fission 

 to form chains (222) similar to those produced by Astomina. 



A detailed survey of the Apostomina has been published by Chatton and Lwoff (28) 

 who have characterized the following genera: Calospira Chatton and Lwoff, Chromidma 

 Gonder (222; Fig. 7. 25, H, I), Foettingaria Caullery and Mesnil (45; Fig. 7. 25, F, G, 

 K), Gymnodinioides Minkiewicz (135; Fig. 7. 25, L), Ophiuraespira Chatton and Lwoff, 

 Pericaryon Chatton, Plioretophrya Chatton and A. and M. Lwoff, Phtorophrya Chatton 

 and A. and M. Lwoff, Polyspira Minkiewicz, Spirophrya Chatton and Lwoff (Fig. 7. 

 25, E, M), Synophrya Chatton and Lwoff (Fig. 7. 25, J), Traumatiophora Chatton and 

 Lwoff, Vampyrophrya Chatton and Lwoff. The genus Chromidina also has been assigned 

 to the Astomina by some workers. 



Suborder 6. Astomina 



These are parasites without a cytostome. The body is often uniformly 

 ciliated but there is sometimes a small naked area at the anterior pole. 

 The average length, for the majority, probably falls within the range, 

 200-500[jL, but such species as Haptophrya gigantea, H. michiganensis 

 (225), and Mesnilella radiata (36) may reach lengths of 1.5-2.0 mm. The 

 cortex shows little specialization, although it ranges from a very thin 

 zone in some coelozoic species to a layer 1.0-2.0[i, thick in certain intestinal 

 parasites. 



