MYCETOZOA. 911 



The elaters are thickened spirally, the tubes of a reticulum by circular 

 ridges, by spines, tubercles, or a network of lines. As soon as the 

 capillitium is established, the nuclei of the protoplasm remaining multiply, 

 the protoplasm itself segments, a portion to each nucleus, the nucleated 

 portions become rounded, acquire a membrane, and so pass into chlamydo- 

 spores. 



The sporocyst is now fully formed. It has a membranous wall, single 

 or double, of varying thickness, white, black, violet, red, yellow, brown, 

 sometimes smooth, sometimes ornamented with ridges or tubercles. When 

 it has a peduncle, that structure is also membranous, hollow, closed or open 

 at its apex, empty, or rilled with various descriptions of useless materials. 

 A drying process sets in, and the sporocyst becomes brittle and breaks up 

 in different ways. When the capillitium is a system of thickenings of the 

 membrane of the sporocyst, it prevents the collapse of the latter ; when 

 it traverses its cavity, it not only affords strength, but there is reason to 

 believe that it executes hygroscopic movements, aiding partly in the 

 rupture of the walls, partly in the scattering of the spores. Such is the 

 case to a very marked degree with the elaters, and the expansile tubular 

 reticulum of the Arcyriaceae, &c. (supra). 



The aethalium, or spore-forming mass, produced by the aggregation 

 or coalescence of a number of plasmodia, is met with in thirteen genera 

 only, belonging to different families of Endosporea. It takes various shapes, 

 a disc, cake (Fuligo\ ball, or a miniature bush. In Fuligo it may attain 

 a great size, as much as i ft. long and I in. thick. Structurally it may 

 consist of a number of prisms set side by side, of interwoven and anasto- 

 mosing tubes (Fuligo), of branched stems, or finally the parts may so 

 completely fuse as to show no trace of their complex structure. It is often 

 naked, sometimes protected by a thin membrane, or in Fuligo and Lycogala 

 by a cortex composed in the first-named of the dried hypothallus, and 

 the collapsed superficial tubes filled with Calcium carbonate and yellow 

 pigment, the protoplasm having withdrawn to the central tubes. The 

 capillitium of an aethalium follows the type of the family to which it 

 belongs. 



As to the physiological relations of the Mycetozoa, it has been shown 

 that they consume oxygen energetically, are repelled by light, attracted 

 by a supply of food or by moisture, provided that the plasmodium is not 

 ripe for sporulation, when it moves to drier spots. The Sorophora for 

 the most part inhabit dung, one or two decaying vegetable matter ; one 

 of them, Dictyostelium mucoroides^ has been grown in solutions of Hippuric 

 acid and Potassium urate. The remaining Mycetozoa live in moist rotting 

 wood, leaves, or other vegetable debris. It is stated that the spores, 

 whether amoebulae or Jlagellulae, but especially the former, take up foreign 

 bodies, e. g. Bacteria ; so too the plasmodium ingulfs very various materials. 



