588 J(inet W. R(i,f: 



species as corresponding to it. He figures this in his " Manual 

 of the Infusoria " (vol. ii., plate xxix., fig. i) from Stein, and 

 describes the widened entrance or vestibuluni to the pharynx as 

 ■' bearing on its lower edge a single long, stiff seta." This is 

 figured also in Bronn's Klassen und Ordnungen des Thier- 

 Reichs (I. 3. Protozoa, plate G'G, figs. 5a and 5b). Some six or 

 eight individuals show this very clearly, though in most of 

 them it is smaller than the one figured. With iron-haema- 

 toxylin alone, the nucleus, oral groove and flagellum appear 

 black (Fig. 2), but when double stained with eosin they are not 

 so sharply marked, the fiagellum rarely being visible. Double- 

 stained with orange G, it is clearer than with eosin. 



In Fig. 1 the position of the macro-nucleus is shown, but I 

 have never once been able to distinguish a micro-nucleus, and 

 after having used all the usual stains I can definitely state that 

 there has been none present. Occasionally the animal at first 

 sight appeared to have a small nucleus in the position in which 

 one would expect the micro-nucleus to be. but on further 

 examination it has proved to be some foreign body lying on 

 the outside of the animal. In Calkins' Protozoa (page 188) we 

 read : " The functions of the two nuclei are supposed to be re- 

 spectively vegetative and reproductive (Butschli), but this dis- 

 tinction is i>erhaps too sweeping. Julin (93) held that the 

 macro-nucleus stands not only for nutrition, movement, 

 sensation and regeneration, but for asexual division as 

 well, in fact is a ' somatic nucleus,' while the micro-nucleus 

 functions only as a sexual nucleus." On this ground there- 

 fore it might be possible to account for the absence of the 

 micro-nucleus, for the only form of reproduction I have observed 

 as yet is the simple transverse division (Fig. 3), which function 

 we thus see may be carried out in the absence of the micro- 

 nucleus. 



Among the Opali/iae there are three forms represented, one 

 of these the commonest, i.e., the one most often present and 

 in greatest numbers, is O. intestinalis (Stein). A detailed de- 

 scription of this well-known form is unnecessary, but the chief 

 points I have noted are as follows: — It measures from 107 ix. 

 to 214 /x in length and is ciliated equally all over, the cilia 

 being very large. The nuclei are spherical and placed in the 



