and its Reproductive Cells. 49 



head fructification of Mucor stolonifera, that there were some 

 colourless heads which had not the usual round form, but, on the 

 contrary, were spear-pointed ; and when placed under the micro- 

 scope, it was evident that the mass was composed of a number 

 of spherical cells, which, for want of the usual common capsule, 

 had, by gravitation, descended the stem, and had thus caused 

 the capitulum (peridiole) to present the shape mentioned. After 

 this, on watching the mass, which was in water under a slip 

 of thin glass, I saw that each cell took on the form of an 

 Amoeba, and in a short space of time the whole bunch were 

 creeping away in different directions, and the entirety of the 

 capitulum had thus become destroyed. 



Furthermore, I observed that when the stems, or the filaments 

 of the mycelium of this Mucor were cut across and pressed 

 under water, their contents issued forth in the form of spherical, 

 plastic, nucleated cells, which, although so delicate that, by 

 the imbibition of water, they soon burst and disappeared, yet 

 retained their form sufficiently long for me to observe in them 

 a certain amount of polymorphism, which, together with their 

 size, bore a close resemblance to the cells which composed the 

 imperfectly formed peridiole. Thus the whole tubular fila- 

 mentous skeleton of Mucor would appear, as in other instances, 

 to be formed upon a group of polymorphic cells. I shall not 

 go into the detail of the formation of the reproductive cells 

 of Mucor and Achlya. Suffice it to say that in the former the 

 peridiole or capitulum is filled with brown capsuled sporidia, 

 like those of ^thulium, while in Achlya it is filled with mono- 

 or diplo-ciliated polymorphic cells, which in their primary form 

 are spherical, like those oi Pythium (fig. 7 d). 



But each of these forms of Mucor has a filamentous mycelium, 

 with the stems (columellse) of their fructificating heads (peridi- 

 oles) divided by septa into distinct cells ; while Pythium has 

 just the same kind of filamentous mycelium, with (when it fruc- 

 tifies under this form) a dilatation at the end of the bunch of 

 root-like filaments into a spore-cell (analogous to the peridiole 

 of Mucor), which produces a number of monadic cells like those 

 of Achlya (fig. 7) . 



I do not know what changes the reproductive cells of Mucor 

 or Achlya may undergo in the first part of their life, but I 

 should think that they were like those of Pythium and jEtha- 

 lium, which have been above described. 



Thus Pythium produces, then, a fungous mycelium, like Mucor 

 and Achlya, and at the same time that the latter are identical, 

 all three only differ from ^thulium and the Myxogastres generally 

 in their internal contents (viz. cells) growing, after a certain period, 

 under a cellulose (?) coat, instead of nakedly, which causes the 



Ann. ^ Mag. N. Hist. Ser. 3. Fol. xii. 4 



