STRUCTURE. 33 



appearance may be accounted for by supposing the existence 

 of an accurate elevation in the wall of the cell, following a 

 spiral direction from one end of the thread to the other. This 

 supposition would, he thinks, accord well with the optical 

 appearances, and it would account exactly for the undulations 

 of outline to which he alludes. He states that he had in 

 his possession a thread of Trichia clirysosperma, in which the 

 spiral appearance was so manifestly caused by an elevation of 

 this nature, in which it is so clear that no internal spiral fibre 

 exists, that he did not think there could be a doubt in the mind 

 of any person carefully examining it with a power of 500 

 diameters that the cause of the spiral appearance was not a 

 spiral fibre. In Arcyria, threads of a different kind are present; 



FIG. ll.Arcyria incaruata, with portion of threads and spore, magnified. 



they mostly branch and anastomose, and are externally furnished 

 with prominent warts or spines, which Mr. Currey * holds are 

 also arranged in a spiral manner around the threads. In other 

 Myxogastres, threads are also present without any appreciable 

 spiral markings or spines. In the mature condition of these 

 fungi, they so clearly resemble, and have such close affinities 

 with, the Trichogastres that one is led almost to doubt whether 

 it was not on hasty grounds, without due examination or 

 consideration, that proposals were made to remove them from 

 the society of their kindred. 



Very little is known of the development of the spores in 

 this group ; in the early stages the whole substance is so pulpy, 

 and in the latter so dusty, whilst the transition from one to 



* Carrey, "On Spiral Threads of Trichia," in "Quart. Journ. Micr 

 Science" (1855), iii. p. 17. 



