112 A Monograph of the Myxogastres. 



colour of the spores as seen in the mass, passing in some species 

 to deep orange and orange-brown ; similar colours are met with 

 in the sporangia! wall. In the genus Perichaena the inner 

 surface of the sporangial wall is frequently covered with a layer 

 of amorphous granules of lime. In stipitate forms of some 

 species belonging to the genera Arcyria, Heterotrichia, and 

 Trichia, the stem is filled with cells which are either spherical 

 or polygonal from mutual pressure. These cells, when young, 

 contain protoplasm, and the wall gives a cellulose reaction ; 

 they are usually largest at the base of the stem, and become 

 smaller upwards, passing insensibly into normal spores at the 

 point where the stem expands into the sporangium. The tubes 

 of the capillitium frequently pass down between these cells 

 into the stem. It would appear as if the stem cells had 

 originally been intended for tme spores, but owing to the 

 contraction of the base of the sporangium into a stem had been 

 checked in their development. 



CALOTRICHEAE. 

 /CLATHROFTYCHIDMA 



XPERITRICHEAE./ 



ANALYSIS OF THE GENERA. 

 CALOTRICHEAE. 



Sub-sect. TRICHEAE. 

 Maters free, not forming a network. 

 TRICHIA. Elaters with well-developed spirals. 

 OLIGONEMA. Elaters without distinct spirals. 



