48 



PROTOZOA. 



Opalina Park, and Val. (Fig. 33), in young state a roundish nucleus. Micro- 

 nucleus not observed ; no contractile vacuole ; rectum of Anura. 



Sub-order 2. SPIROTRICHA. 



Always with distinct adoral zone, which usually consists of membranellse, 

 and has a more or less spiral course round a peristomial area. The latter is 

 distinguished by other peculiarities from the rest of the body-surface. 



Section 1. Heterotricha. 



With well-developed adoral zone or spiral, and a complete ciliary covering 

 (except Gyrocorys). 



Fam. 1. Plagiotomina. Peristome as a narrow furrow, which usually begins 

 close to the front end and passes along the ventral surface to the mouth, which 

 is either at the middle of the body or at the hind end. The adoral zone 

 stretches from the mouth along the left side of the peristome, and is usually 

 straight. Pharynx tubular. Conchopthirus Stein, ma.n.* single or multiple, 

 f.w. , ectopar. in slime of different laud and f.w. molluscs, 

 in gastral cavity of Actinire ; Placjiotomn Duj., paras.; 



Nydotherus Leidy, with anal tube, 



paras, in intestine of Anura, Insects, 



and Myriapods ; Blepharisina Perty, 



f.w.; Metopus Clap, and L., f.w. and 



m.; Spirost.omum Ehrb. , ma.n. single, 



mi. n. numerous, f.w. and m. 



Fam. 2. Bursarina. Peristome as a 



more or less triangular (apex oralwards) 



field, and not a furrow, as in Plagioto- 

 mina. Pharynx absent or but slightly 



developed. The adoral row extends 



along the left peristome-edge only, or 



crosses over in front as far as the 



right anterior angle of the peristome. 



Balantidium Cl. and L., paras, rectum 



of man, pig, Amphibia, body cavity 



of Polychretes-; Balantidiopsis Biitschli, 



intestine of Rana ; Condylostoma Duj., 



mi. n. numerous, f.w. and m. ; Bursaria, 



0. F. Miiller, large size, ma. n. long, 



mi. n. numerous, f.w. 



Fam. 3. Stentorina. Body elongated. Peristome short and at front end. 

 Its two edges sometimes prolonged into wings. The adoral spiral passes either 

 across the front end of the peristome to the right corner of the same, or 

 completely surrounds the peristomial area. Undulating membrane absent. 

 The peristomial surface is ciliated and spirally striped. Pharynx tubular. 

 Climacostomum Stein, f.w.; Stcntor Oken (Fig. 31), ma.n. long, mi.n. numerous, 

 sometimes fixed and with gelatinous tube, f.w.; Folliculina Lam. with peris- 

 tomial wings, usually inhabits chitinous tubes, f.w. and m. 



Fam. 4. Gyrocoryna. Bell-shaped, anterior end rounded, posterior end as 

 caudal appendage projecting from the bell ; a ventral furrow with cilia, a row of 



* ma.n., mi.n. are abbreviations of macro- and micronucleus respectively; 

 f.w. and m. similarly standing for fresh-water and marine. 



FIG. 39. Paramce- 

 ciumaurelia, after 

 Ehrenberg. M 

 month ; Cv con- 

 tractile vacuoles 

 with canals. 



FIG. 40. Balantidium 

 coli, with two con- 

 tractile vacuoles 

 after Stein. Near 

 the nucleus lies a 

 starch grain which 

 has been eaten ; a 

 ball of excrement 

 is passing out per 

 anura at the hind 

 end. 



