SPORES SWALLOWED BY HORSES 



83 



are rubbed upon it either directly from gills or from a recent spore- 

 deposit, the spores germinate and fruit-bodies are subsequently 



Fig. 52. — Coprinus sterquilinus. Camera-lucida drawing of a young myceliiun 

 produced in the course of about 24 hours from a spore sown in a sterile culture 

 medium. The spore was placed in a thin film of dung-agar on a slide in a 

 moist Petri dish. The mycelivun was fixed in formalin-acetic-alcohol, was 

 stained with iron-alum hsematoxylin, and was counterstained with light-green. 

 The germ-tube issued from the terminal germ-pore of the black spore shown 

 in the centre of the drawing and it developed into a mycelium with coarse 

 radiating hyphae, up to the present without a single cross-wall : a, at this spot 

 there was a small ungerminated spore which probably prevented the mycelium 

 from sending out a branch in this direction ; the hypha b almost conceals a 

 hypha beneath it, and a short hypha is entirely concealed by the hypha c ; 

 n n, nuclei with thin inconspicuous membranes and clear contents except for 

 the relatively large and well-stained nucleoli ; v v, vacuoles in the cytoplasm. 

 The number of the nuclei in the whole mycelium was carefully counted and found 

 to be 233, so that the mycelium which, as yet, is unicellular, is a single coenocyte. 

 The nuclei, as at n n, are usually solitary ; but, at the ends of certain hyphae, 

 e.g. d and e, where nuclear division has evidently just been very active, the 

 nuclei are in pairs : there is no evidence of conjugate nuclear divisions at this 

 stage of development. Winnipeg material. Drawn by A. H. R. Buller and 

 Ruth Macrae. Magnification, 850. 



