STRUCTURE, 83 
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 chrysosperma, 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; 
Fic. 11.—Areyria incarnata, 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 
* Currey, ‘On Spiral Threads of Trichia,” in ‘Quart, Journ. Mier 
Science ” (1855), iii. p. 17. 
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