48 THE MICROSCOPE AND ITS REVELATIONS. 



differing in many respects from that of the animalcule which became en- 

 cysted. According to M. Jules Haime, by whom this history was very 

 carefully studied, 1 the form to be considered as the larval one, is that 

 shown in Fig. 308, A-E, which has been described by Prof. Ehrenberg 

 under the name of Oxytricha. This possesses a long, narrow, flattened 

 body, furnished with cilia along the greater part of both margins, and 

 having also at its two extremities a set of larger and stronger hair-like 

 filaments; and its mouth, which is an oblique slit on the right-hand side 

 of its fore-part, has a fringe of minute cilia on each lip. Through this 

 mouth large particles are not unfrequently swallowed, which are seen 

 lying in the midst of the endosarc without any surrounding vesicle; and 

 sometimes even an Animalcule of the same species, but in a different 

 stage of its life, is seen in the interior of one of these voracious little de- 

 vourers (B). In this phase of its existence, the Trichoda undergoes mul- 

 tiplication by transverse fission, after the ordinary mode (c, D); and it is 

 usually one of the short-bodied ' doubles ' (E) thus produced, that passes 

 into the next phase. This phase consists in the assumption of the globu- 



FIG. 308. 



Metamorphoses of Trichoda lynceus .-A, larva (Oxytricha} ; B, a similar larva, after swallow- 

 ing the animalcule represented at M; c, a very large individual on the point of undergoing fission; 

 D, another in which the process has advanced further; K, one of the products of such fission; p, 

 the same body become spherical and motionless; o, aspect of this sphere fifteen days afterwards; 

 H, later condition of the same, showing the formation of the cyst; i, incipient separation between 

 living substance and exuvial matter; K, partial discharge of the latter, with flattening of the 

 sphere; L, more distinct formation of the confined animal; M, its escape from the cyst; N, its ap- 

 pearance some days afterwards: o, more advanced stage of the same; p, Q, perfect Aspidiscce, one 

 as seen sideways, moving on its bristles, the other as seen from below (magnified twice as much as 

 the preceding figures). 



lar form, and the almost entire loss of the locomotive appendages (F); 

 in the escape of successive portions of the granular sarcode, so that 

 1 vacuoles ' make their appearance (G); and in the formation of a gelatinous 

 envelope or cyst, which, at first soft, afterwards acquires increased firm- 

 ness (H). After remaining for some time in this condition, the contents 

 of the cyst become clearly separated from their envelope; and a space 

 appears on one side, in which ciliary movement can be distinguished (i). 

 This space gradually extends all round, and a further discharge of gran- 

 ular matter takes place from the cyst, by which its form becomes altered 



i " Annales des Sci. Nat.," Ser. 3, Tom. xix. (1853), p. 109. 



