898 PROCEEDINGS OF THE AMERICAN ACADEMY 



such a time is clearly seen. There are no appendages whatever 

 about, or belonging to the mouth ; not even the flagelliform body {Ji) 

 has anything to do with it, but is attached to the body at a very sensi- 

 ble distance {fi^) behind it. It would seem, therefore, to be dependent 

 upon the simple cilia around it for the transfer of food to its lips. 

 From the mouth the cesophagus (o?) passes obliquely backwards and 

 toward the dorsal region, at least half-way through the body, and then 

 terminates, rather abruptly, just before the contractile vesicle, but a 

 little to the right side (fig. 3, ce) of the axial plane. At the mouth it 

 is widest antero-posteriorly, but suddenly narrowing a little, it after- 

 wards gradually lessens its calibre as it extends into the body, and 

 finally ends as just described. The whole track of this channel is 

 much more readily seen than the mouth. The food is taken in such 

 excessively small particles that its entrance into the mouth cannot be 

 detected with any degree of satisfaction ; and a single digestive vacu- 

 ole {dv) requires from twenty minutes to half an hour to form and fill ; 

 and although it may be comparatively quite large, even two thirds of 

 its fullest capacity, yet so infinitesimally minute are the particles that 

 even indigo or carmine is not readily seen, although it may be the 

 only kind of food present. Beyond this point, however, these coloring 

 matters become rapidly visible, so that when a vacuole is fully formed, 

 the indigo or carmine is as conspicuous as in any other infusorian. 

 These vacuoles are very large, in fact equalling in size the contractile 

 vesicle ; and as they form sometimes pretty far back, they are apt to 

 obscure the latter ; without doubt thus causing this vesicle to be mis- 

 taken for one of them, since they bear a certain resemblance to it. No 

 anus was detected during these investigations, although the specimens 

 at times were kept w^ell fed. 



The locomotive organs. The most prominent among the cilia is the 

 so-called flagellum {fi). This, however, is not a single filament, as 

 has usually been asserted, but owing to the manner in which it is used 

 it very naturally appears to be so. Most frequently its compound na- 

 ture becomes apparent when the numerous cilia of which it is com- 

 posed divide into two groups (fig. 7, fl fi^), thus simulating a double 

 flagellum.* At other times, after having divided into two groups, they 



* Claparede, loc. cit., speaks of frequently noticing that some of the Ceratiums, 

 &c. appeared to have a double flagellum. Probably they were a group of cilia 

 divided as here described. 



