FLAGELLATE INFUSORIA AND ALLIED ORGANISMS. I! 



animal withdraws itself into its calyx, although this is by 

 no means always the case (fig. 12^ b). Clark was probably 

 right when he attributed this power of closing the shell to 

 young forms. Sometimes the calyx is not circular, but is 

 triangular. Of this, however, the author is not quite 

 certain. 



The height of the calyx is, on an average, 0*014 mm. The 

 organism is attached to the base of it by means of a thread 

 springing from the hinder end of the body ; it is this thread 

 which Clark rightly compares with the hinder flagellum of 

 many heterotrich Flagellata, as, for instance, many forms of 

 Cercomonas. The contractile vacuole is a little distance 

 rom the point of origin of this thread of attachment. The 

 fflagellum, of considerable length, springs from the anterior 

 end and stands out straight from the body when it is in its 

 usual state of rest (fig. 12, c). The extreme end alone 

 vibrates or bends at this time, throwing the minute particles 

 of food with considerable force against the beak-like pro- 

 minence. When, however, the organism is retracted into its 

 case the flagellum is rolled up (fig. 12, b) so that it is pro- 

 tected by the case. 



The lip- or beak-like prominence for the reception of food 

 is very noticeable, and appears to resemble most nearly the 

 one found in Antophysa. It is seen, by observing it in dif- 

 ferent positions, to be strictly a leaf-like broadened prolonga- 

 tion (fig. 12, c and d). A vacuole formed before the ingestion 

 of food has never been observed, but one is produced as soon 

 as a small particle of food has been thrown between this 

 prominence and the base of the flagellum. The vacuole so 

 formed takes in the food and distributes it in the body. 

 Clark placed the mouth at this spot, although, there is no 

 doubt, that no such orifice exists preformed for the reception 

 of food, but only that a particular spot on the surface of the 

 body is set aside for this purpose. Clark has observed that 

 the food remains are extruded a little above the spot at 

 which the food is ingested, but the author has not yet 

 followed out the act of defaecation. 



Nothing is noticeable in the body proper of the organism. 

 Clark, however, has observed in the two species of this genus 

 which he examined, a furrow extending along the whole 

 length of the body, beginning at the base of the flagellum, 

 and traceable to the point of origin of the posterior thread of 

 attachment. He believes that this groove is distinguishable 

 by a peculiar contractility. The body itself is possessed of 

 a certain contractility, as it has been seen to become spherical 

 without the aid of the posterior thread. The nucleus has 



