INTRODUCTION 



37 



Haptophrya giganfea and Poli/spiro delagei. In arboroid colonies 

 the individuals are attached directly end to end as in Chlorodendron. 

 suhsahum or hy longer or shorter stalks in a branching, often 

 bush-like colony [Hyalohryon deformans (Fig. 19), Dinobryon ser- 

 tidaria (Fig. 126, p. 529), Epistylis iimhellaria (Fig. 210, p. 502), 



M 



Fig. 15 Fig. 16 



Fig. 1.5. — A bilaterally .symmetrical flagellate, Giardia muris Grassi. AX, axostyle; 

 B, blepharoplast; BB, basal body; C, centriole; E, eudosome; N, nucleus; PL, 

 parabasal body; RH, rhizoplast. (After Kofoid and Swezy.) 



Fig. 16. — A bilaterally sjTnmetrical ciliate from Vroleptus mobilis. A double 

 indi\adual formed by fusion of two individuals after conjugating. With two mouths 

 and adoral zones (a. z.) ; two sets of cirri (/); and two sets of macronuclei (M) and 

 micronuclei (rn). For structure of single individual see Frontispiece. (Original.) 



Carchesium polypinum, Zcothamnium arhuscnda, etc.]. In the major- 

 ity of these arboroid colonies each individual is borne on its own 

 stem which branches from a common stalk. In some cases, how- 

 ever, especially amongst the flagellates, each stalk bears a cluster 

 of individuals as in Cladomonas fruticnJofsa, Anthophysa vegetans or 



