EXPLANATION OF PLATE XVII. 

 Fig. 



1-4. Dendromonas virgaria, Weisse sp., vol. i. p. 266. — i, Adult colony-stock 

 or zoodendrium, x 800 ; 2, younger and less ramified zoodendrium, as 

 figured by Stein, ' Wiegmann's Archives,' 1 849, as a probable young condition 

 of Efistylis anastatica ; 3, an isolated monad, X 2000 ; 4, colony of two 

 monads in process of division by longitudinal fission. 



5-7. Cladonema laxa, S. K., vol. i. p. 265. — 5, adult colony, x 1000 ; 6, a monad 

 dividing by longitudinal fission; 7, a single monad ingesting a food-particle 

 towards the posterior region of its periphery, x 3000. 



8. Dendromonas pusilla, Schmard. sp., vol. i. p. 266, x 250. 

 9-n. Anthophysa SOCIAlis, From., vol. i. p. 272. — 9 and 10, Colony-stocks, after 

 De Fromentel, x 350; 11, head of colony-stock, including centrally an 

 encysted monad, x 1500, after Biitschli. 



12. Cephalothamnium cuneatum, S. K., vol. i. p. 273, X 1250. 



13-26. Anthophysa vegetans, Miill. sp., vol. i. p. 267. — 13-15, Branching colony- 

 stocks and detached monad clusters, or ccenobia, as originally delineated 

 by O. F. Miiller, x 50; 16, a typical, erect, shortly branching colony- 

 stock, with four terminal monad-clusters or ccenobia, x 400 ; 17, a portion 

 of common stem, showing its compound or fibrous nature ; 18 and 19, 

 two colonies in which the monads, being fed with carmine, have after 

 passing it through their bodies, incorporated the pigment from the points a, 

 into the substance of the common stem, x 800 ; 20-22, sporocyst, showing 

 progressive phases resulting in the liberation of the contents in the form of 

 simple monadiform germs, x 800 ; 23, the empty sporocyst, showing its 

 composition of an outer firmer and inner more delicate and elastic mem- 

 brane ; 24, monadiform germs liberated from sporocyst, x 2000 ; 25, subse- 

 quent resting condition of the same germs ; 26, branching zoodendria 

 deri\-ed from these resting spores, the monad clusters having become de- 

 tached. 



27-32. Cephalothamnium c^espitosa, S. K., vol. i. p. 272. — 27 and 28, Adult com- 

 pound colony-stocks, X 1200; 29-31, single stalked monads, those in the last 

 two figures emitting pseudopodia from within the distal region only, or from 

 the entire surface of their peripheiy, X iSoo ; 32, a zooid dividing by trans- 

 verse fission. — The size of the zooids in the descriptive account of this 

 species has been accidentally set down as 1-5000", instead of 1-3000." 



