FUNGI. 455 



Distribution. Desmidiece occur in all quiet pools of pure water, at 

 the bottom or adhering to other plants. Diatomece are universally dif- 

 fused, not only in fresh water, but in the sea and on moist ground, in all 

 of which situations their siliceous cell- walls cause their remains to accu- 

 mulate, if left undisturbed, until they form actual mineral strata. 



VOLVOCINE^E are microscopic bodies swimming in fresh water by the 

 aid of cilia arranged in pairs upon the surface of a common semigelatinous 

 envelope, the pairs of cilia each belonging to a green corpuscle resembling 

 the zoospore of a Confervoid, imbedded in the periphery of the common 

 envelope. .Reproduction by the development of each corpuscle into a 

 new colony, the whole being set free by the solution of the parent 

 envelope, or by conversion of the corpuscles into encysted resting-spores 

 like those of (Jonfervoids. These curious and beautiful objects, found in 

 similar situations with the Confervoids, appear more closely related to that 

 group of organic beings than to any form distinctly recognizable as mem- 

 bers of the Animal Kingdom, the persistence of the power of motion 

 throughout the period of vegetative life being the only animal (?) character. 

 Genera : Votvox, Lam. ; Pandorina, Ehreub. (tig. 508, Dj j Stephano- 

 , Cohn ; (fonium, Lam. 



Division II. Fungi. 



Cryptogamous plants consisting of long thread-like, tubular, gene- 

 rally branching hyphse, or of branching series of cells interwoven 

 into a mass which is in some cases microscopic in dimensions and 

 in others of great extent, nourished on organic substances as para- 

 sites or as saprophytes, and entirely destitute of chlorophyll or 

 similar pigments. .Reproduction effected by both sexual and 

 asexual means. 



PHYCOMTCETES. 



Diagnosis. Fungi consisting of a mycelium of long, densely 

 ramifying tubes, and bearing both sexual and asexual organs of 

 reproduction. The asexual organs of reproduction (zoosporanyia, 

 coiiidia, and sporangia) are functionally of equal value with those 

 produced by sexual agency (oospores and zygospores) that is, the 

 oospores or zygospores (as the case may be) produce either zoospo- 

 raiigia or conidia or sporangia, and on the same plant, but a little 

 later, either oospores or zygospores again ; the nrst or asexual 

 class of these also reproduce both themselves and the second or 

 sexual class a little later. 



This Order may be divided into three Suborders, in which the 

 habits of life and growth vary. 



Suborder 1. SAPROLEGNIE^E. Fungi growing for the most part 

 in water, and chiefly on the dead bodies of insects, and consisting 



