282 DESCRIPTION OF \_Polygastrka. 



Genus CII. Trichodiscus. The rayed-disc Animal- 

 cules. — Body depressed, marginated with a single row of 

 setaceous tentacules ; vibratile cilii and teeth absent ; no 

 pedicle : the mouth truncated (direct). 



The flat disciform shape of these Infusoria resembles 

 those of the genus Arcella, but, unlike the latter, these are 

 soft and shell-less, with the rays stiff, like bristles. A 

 central opening, and probably a large lateral gland, have 

 been recorded by Ehrenberg, who likewise states that he 

 has seen, though indistinctly, numerous digestive cells, 

 but that reception of coloured food was not observed, nor 

 the situation of the anal orifice. 



437. Trichodiscus sol. The su7i Trichodiscus. — 

 Figures 267 and 268 have a depressed almost flat body, 

 hyaline or yellowish, with variable rays. The motion of 

 this species is very sluggish; it often remains for a long 

 time inert. Found amongst conferva. Diameter, without 

 the rays, l-430th to 1-2 10th. 



Genus CIII. Podophrya. The pedicled and rayed 

 Animalcules. — Enchelia devoid of vibrating cilii and teeth; 

 their bodies are spherical, pedicellated (free), and covered 

 with setaceous tentacules. The mouth truncated (direct). 

 In organization they are similar to Actinophrys, with a 

 stiff stalk. 



438. 'PoBOPHRYA Jixa {Trichoda fixa, M.) The fresh- 

 water Podophrya has a spherical, turbid, whitish body, with 

 a glass-like pedicle, slightly excised at the extremity. The 

 rays or seta2 have their extremities capitate, and equal the 

 diameter of the body in length, as represented at Jigures 

 269, 270 : the latter exhibits it with two animalcules it has 

 seized. Dr. Ehrenberg states the seizing or catching power 



