236 SCIENCE PROGRESS 



warrant the assumption. The spores of A in pure culture 

 reproduce A, and the spores of the second form B produce only 

 B — it is not possible to grow A from B, or vice versa. Yet the 

 two forms are connected by the same mycelium. The deter- 

 mination of their connection with the mycelium which bears the 

 kohlrabi heads rests on : (i) The possibility of tracing the 

 hyphae through the tangle which covers the garden ; and 

 (2) the production of similar swellings on the hyphae cultivated. 



In view of the difficulty of the first, and the probability 

 that the kohlrabi heads are not diagnostic, it would seem 

 preferable to regard the two moulds as " weeds " in the fungus 

 garden corresponding to the Xylaria in the termite comb. It is 

 not possible to determine, by tracing the hyphae, that the 

 termite Xylaria is not connected with the mycelium which 

 bears the spheres. 



It is interesting to note that Holtermann, working with 

 termite combs in crystallising dishes, obtained only a dense 

 growth of hyphae which filled the dish. Apparently he wetted 

 the combs and used vessels which were too small. 



A Parallel Agaric Mycelium 

 So far no reason has been given why the termite sphere 

 should be thought to be connected with the agaric rather than 

 with the Xylaria. Indeed, the constant occurrence of the Xylaria 

 suggests that the latter is the fungus really cultivated. But 

 another Ceylon agaric, not connected with any insect, affords 

 evidence which appears to justify the view taken. This agaric, 

 Entoloma microcarpum, grows, not from the usual mycelium 

 of fine hyphae united into strands, but from a thin cake of 

 closely packed spheres. The separate spheres are about the 

 same size as those on the termite comb, and like the latter 

 they appear to be composed of spherical cells. On teasing 

 them out, it is found that the spherical cells are borne singly 

 on the hyphae, and form only a coating on the exterior, while 

 the internal hyphae swell out into oval or irregular cells, 

 arranged either singly or in chains in the course of a hypha. 

 In some instances these internal chains of cells show branching 

 of the same type as that in the termite sphere. There is, 

 however, no definite arrangement of the hyphae — the interior of 

 a sphere is a confused tangle of swollen cells and hyphae. 

 Towards the exterior some hyphae are arranged radially, and are 



