VorticeUina.'] THE INFUSORIA. 265 



a variety of shapes, moves briskly in the water, and forms 

 the genus Ophrydia of Bory St. Vincent. Ehrenberg has 

 divided this species into two varieties, founded on the 

 shape of the bell ; when they are nearly globular, he calls 

 them campanulata ; when pointed, pyriformis." 



403. VORTICELLA pictd. The dotted Vorticella has an 

 ovate, conical, campanulate body, the frontal portion 

 dilated, and its margin slightly expanded. The pedicle is 

 very slender, and curiously marked throughout its length 

 with red dots. Length 1-1 150th to l-570th ; stalk four 

 to five times as long. 



Genus XCI. CARCHESIUM. The tree and trumpet 

 Animalcules are closely allied to the preceding genus, from 

 which they are distinguished by having their spirally flexible 

 pedicle branched, in consequence of imperfect self-division. 

 The bodies upon the pedicle are all of the same form. 

 The organization of this genus is not so well known as 

 Vorticella and Epistylis. A simple wreath of cilii, which 

 during quick vibration appears double, is observable ; and 

 another, at certain periods, at the posterior part of the 

 body: within the pedicle, a transversely-folded thread- 

 like muscle is observed during contraction; the mouth 

 (which is lateral) and polygastric alimentary canal are dis- 

 tinct. Of the propagative system, whitish ova, granules, 

 and a contractile bladder, are seen ; but a spermatic gland 

 is not very distinct. Imperfect longitudinal self-division 

 is a very marked character ; the growth of gemmae has 

 been observed, and the periodical separation of the body 

 from the stalk gives rise to free animalcules, as in Vorticella. 



404. CARCHESIUM polypinum (V.polypma, M.) The 

 bell-like Animalcule of Leeuwenhoek has a conical, cam- 



