32 



THE MICROSCOPE AND ITS REVELATIONS. 



Fig. 295. 



the 'flagellated ' agree with the * ciliated' Infusoria in ordinarily drawing 

 their nutriment from organic compounds; and it seems clear that, 

 although unpossessed of a mouth, they can introduce solid food-particles 

 into the interior of their bodies. It is, however, not a little remarkable 

 that (according to the statement of Messrs. Dallinger and Drysdale) 1 

 these Flagellata like Bacteria and other forms referred to the group of 

 Fungi can be cultivated in Cohn's ' nutritive fluid ' ( 303, note), which 

 consists only of tartrate of ammonia and mineral salts, without any al- 

 buminous matter. 



424. A large series of more complex forms of Flagellate Infusoria has 

 been recently brought to our knowledge by the researches of the late 

 Prof. James-Clark (U. S.), 2 followed by those of Stein and Saville Kent. 

 In some of these, a sort of collar-like extension of what appears to be 

 the sarcodic ectosarc, proceeds from the anterior extremity of the body 

 (Fig. 295, cl), forming a kind of funnel, from the bottom of which the 

 flagellum arises; and by its vibrations a current is produced within 

 the funnel, which brings down food-particles to the ' oral disk ' that 

 surrounds its origin, where the ectosarc seems softer than that which 

 envelops the rest of the body. Towards the base of the collar, a nucleus 

 (n) is seen; while, near the posterior termination of the body, is a single 



or double contractile vesicle cv. The body 

 is attached by a pedicle proceeding from its 

 posterior extremity, which also seems to be a 

 prolongation of the ectosarc. These Ani- 

 malcules multiply by longitudinal fission; and 

 this, in some cases (as in the genus Monosiga], 

 proceeds to the extent of a complete separa- 

 tion of the two bodies, which henceforth, as 

 in the ordinary Monadina, live quite inde- 

 pendently of each other. But in other forms, 

 as Codosiga, the fission does not extend 

 through the pedicel ; and the twin bodies be- 

 ing thus held together at their bases, and 

 themselves undergoing duplicative fission, 

 clusters are produced which spring from com- 

 mon pedicels (Fig. 296). And by the exten- 

 sion of the division down the pedicels, them- 

 selves, composite arborescent fabrics, like 

 those of Zoophytes, are produced. 



425. In an another group, a structureless 

 and very transparent horny calyx, closely re- 

 sembling in miniature the polype-cell of a 

 Campanularia (Plate xx.), forms itself around 

 the Dody of the Monad, which can retract 

 itself into the bottom of it. And in the 

 genus Salpingceca both calyx and collar are 

 present. In some forms of this group, mul- 

 tiplication seems to take place, not by fis- 

 sion, but by gemmation; and, as among 



Hydroia Polypes, the gemma may either detach themselves and live inde- 

 pendently, or may remain in connection with their parent-stocks, form- 



1 " Monthly Microscopical Journal," Vol. xiii. (1875\ p. 190. 



2 See his Memoirs in "Ann. Nat. Hist.," Ser. 3, Vol. xviii. (1866); ibid., Sen 

 4, Vol. i. (1868); Vol. vii. (1871); and Vol. ix. (1872). 



Single zooid of Codosiga umbel- 

 lata:cl, collar; n, nucleus; cv, 

 double contractile vesicle. 



