AMONG SIMPLE SAECODE OEGANJSMS. 423 



plasm lump which, as we have already seen, constitutes the fully- 

 developed state of the active and voracious Vampyrella. 



Cienkowski divides his group of the Monadina into two sub- 

 ordinate ones : — 



I. Monadina zoospobea. — Eeproduction effected by the for- 

 mation of numerous mobile spores. 



1. Monas (Protomonas, Haeckel). 



2. Pseudospora. 



3. Colpodella. 



TI. Monadina tetraplasta. — Eeproduction effected by the 

 formation of two or four Actinophrys-lAke bodies. 



4. Yampyrella. 



5. Nuclearia*. 



Among the most important researches on the lowest forms of 

 life which must be brought under this review are those of Messrs, 

 Dallinger and Drysdale on a group of minute flagellate organisms 

 obtained from putrifying infusions of fish, and described by 

 these investigators under the general name of "Monads "f. 



By the aid of very high powers (^^ of an inch object-glass), 

 and by employing an ingeniously constructed " moist chamber," 

 Messrs. Dallinger and Drysdale have followed up the life-history 

 of these organisms, and have discovered, common to them all, 

 certain phenomena which are full of significance in the history of 

 development. 



Among several forms whose development has been carefully 

 traced by them, we may take, as a suificiently illustrative example, 

 one to which they refer under the name of " the calycine monad J" 

 (fig. 13). It has a conical shape (A), y^nny ^o 3^ o^ ^^ ii^^^ ^^ 

 length ; the broad end carries four flagella, which spring from a 

 common root, while the opposite end tapers away to a point. A 

 shallow longitudinal depression extends backwards along each 

 side, giving to the broad end an hourglass-shaped outline. It con- 

 tains a large nucleus and two rhythmically contracting vacuoles. 



The first phenomenon observed in its life-history is a multipli- 



* Niiclearia has been described above, and reasons given why it ought not to 

 be associated with the Monadina of Cienkowski (see p. 386). 



t Eev. W. H. Dallinger and J. Drysdale, M.D., " Eesearches on the Life- 

 History of the Monads," Monthly Microsc. Journ. vols, x.-xiii. 1873-75. 



\ In no instance do the authors give a systematic name to the organisms 

 which form the subject of their investigations, and to which they always refer 

 under vernacular designations. 



