Eiichelia.^ THE INFUSORIA. 283 



of this animalcule is very interesting to observe. As soon 

 as a specimen of the quick vibrating Trichodina grandinella 

 approaches to and comes in contact M'ith its tentacules it 

 is immediately taken prisoner, ceases to vibrate, and 

 stretches out its cilii backwards (Opisthotonus) . On the 

 whole, this species resembles the Acineta, from which it is 

 separated by Dr. Ehrenberg, who supposes it to possess a 

 discharging orifice, though its situation is unknown. 

 Found among dust-like matter upon the surface of pond 

 water, and perhaps, says Dr. Ehrenberg, in the sea 

 (Copenhagen). Diameter l-430th. 



Genus CIV. Trichoda. The hair Animalcules. — 

 Body devoid of hairs or cilii; mouth truncated (oblique), 

 destitute of teeth, but provided with vibratile cilii, and 

 having a lip, but no neck. The polygastric apparatus is 

 satisfactorily proved by the employment of coloured food, 

 and the posterior anal spot is also known. The oblique 

 surface of the mouth forms a very characteristic upper 

 lip-like projection. In T. pyrum only has self-division 

 been observed. All the species are colourless. 



439. Trichoda pura {Kolpoda pyrum, M.) The clear 

 Trichoda, represented at figures 271, 2, 3, has an oblong 

 club-shaped body, with small vesicles. The anterior part 

 is attenuated, and the mouth lateral. Common in vegetable 

 infusions, usually with Cyclidium glaucoma. Size l-720th. 



440. Trichoda Nasamoiium. The Lybian Trichoda. — 

 Body cylindrical, extremities equally obtuse, the mouth 

 large and elongated laterally. Size 1 -288th. 



441. Trichoda ovata. The egg-shaped Trichoda. — 

 Body ovate, turgid, attenuated anteriorly ; mouth small 

 and lateral. Size 1 -480th. 



