164 NOTES ON MYCETOZOA. 



capillitium, and the mottled spores. I give the specific name strawi- 

 nipes on account of the straw-colom^ed stalks ; these and the peculiar 

 striicture of the spores constitute tha essential points of difference 

 which distinguish this species from P. compressum, its nearest ally. 

 Didymium Trochus, n. sp. (PI. 386, fig. 1). Among the 

 interesting species which the search in straw-yards has yielded 

 during the past year is a Didijmium which appears to he iindescribed, 

 and has not been met with in any of the collections we have 

 examined. It is allied to D. difforme Duby in possessing a convex 

 egg-shell-like upper sporangium-wall rising from a broad base ; it 

 has also a somewhat rigid and sparse capillitium. It differs from 

 D. difforme in the sporangia being provided with a stalk, in the 

 presence of a prominent columella, and in the warted spores. The 

 prevailing shape of the sporangia is that of a peg-top (hence the 

 specific name), but much diversity of form occurs, as will appear in 

 the account given later. We first discovered the species, with both 

 stalked and sessile sporangia, on straw at Chaul End, May 6th, 

 1897. On July 8th we received a further supply from Mr. Saunders, 

 gathered in a stackyard at Barton. The sporangia were mostly 

 top-shaped, but in some the stalks were very short. On Oct. 28tli 

 Mr. C. Crouch sent us a large gathering which he had found on "a 

 heap of turnips and haulm" at Kitchen End, near Ampthill. A 

 part of the growth was in "buttercup yellow" plasmodium, some 

 of which he sent with the ripe sporangia in a box packed with 

 moss ; during the transit by post the plasmodium crawled on to 

 the moss, and there formed sporangia. In this gathering the 

 stalks are almost all well developed. In the same month we 

 received from Mr. E. S. Salmon a small gathering on dead leaves, 

 which he had obtained in April, 1897, in the grounds at Clevelands, 

 Reigate ; the sporangia are sessile, and in this respect resemble 

 many of those of our first gathering at Chaul End. The descrip- 

 tion of the species is as follows : — Plasmodium bright yellow, 

 among dead leaves, straw, &c. ; sporangia 0-7 to 1 mm. diam., 

 pale ochre or white, hemispherical or top-shaped, stalked or sessile ; 

 sporangium-wall of two layers, the outer brittle and shell-like, 

 composed of closely compacted angular or stellate crystals of lime, 

 forming a hemispherical cap fitting on to the yellow-brown thickened 

 margin of the broad columella ; the inner layer membranous, 

 entirely free from lime, usually adhering to the outer layer ; colu- 

 mella ochraceous, smooth, convex, nearly as broad as the spor- 

 angium, filled with large and beautifully stellate snow-white 

 crystalline masses of lime, which also extend downwards into the 

 interior of the stalk ; in many sporangia where the stalk is almost 

 or entirely wanting the surface of the columella is beset with pro- 

 jecting lobes filled with stellate crystals, and often attenuated 

 upwards into the threads of the capillitium ; stalk yellowish brown, 

 obconic or cylindrical, furrowed and wrinkled, often narrow at the 

 point of attachment to the straw, and easily falling off"; capillitium 

 colourless or purple-brown, not profuse, persistent, the threads either 

 almost simple from a broad base, or branched above, or anastomosing 

 and forming a loose network ; in the last case the threads are often 



