EXPLANATION OF PLATE XII. 

 Fig. 

 1-4. Phalansterium digitatum, St. (after Stein), vol. i. p. 362. — i, Adult branching 



mucilaginous zoocytium, x 450; 2-3, early conditions of a similar zoocytium ; 



4, a single animalcule, x 1200 ; c/, rudimentary collar. 



5-g. Phalansterium consociatum, Cienk., vol. i. p. 362. — j. Adult discoidal colony, 

 X 650 (after Stein) ; 6, an isolated animalcule further enlarged ; 7 and 8, 

 encysted zooids (after Cienkowski), the one at Fig. 8 having developed a 

 hard tricarinate capsule ; 9, an animalcule dividing by longitudinal fission. 



10. Spongomonas discus, St., voL i. p. 2S7, X 650 (after Stein). 



11-14. Spongomonas intestinalis, Cienk. sp., vol. i. p. 287. — 11, Filamentous adult 

 colony, natural size (Cienk.) ; 1 2, extremity of similar colony enlarged, 

 showing disposition of contained animalcules; 13, an isolated monad, 

 X 650 ; 14, fragment of gelatinous granular zoocytium, showing at a normal 

 zooid ; 6, two zooids derived from the longitudinal fission of such as a ; c, a. 

 retracted and encysted zooid ; d, e,f, various multiplicative phases by which 

 a primary quiescent or encysted zooid has become divided into two, four, or 

 eight spore-like bodies, x 650 (12-13 after Stein). 



15, 16. Spongomonas uvella, St. (Stein), vol. i. p. 288.— 15, An adult colony, x 650; 

 16, initial condition of such a colony as founded by a single animalcule. 



17-23. Spongomonas sacculus, S. K., vol. i. p. 288.— 17, Adult colony, x 10 ; 18 and 

 19, showing proportionate [growth of same colony in three days as observed 

 by the author, natural size ; 20, fragment of granular zoocytium, containing 

 two normal biflagellate and a single encysted subdividing zooid, x 1200 ; 21 

 and 22, isolated zooids, X 1200; 23, encysted zooid dividing by transverse 

 fission. 



