406 OBIGINAL AETICLES. 



compressed, but the process is a slow one, depending upon the 

 gradual decomposition of a part of the vegetable matter, and has a 

 very definite limit. 



A grave is naturally frequently sunk till the digger reaches a 

 harder layer of soil, which forms a point d'appui for the back of the 

 skull, or, in a cist, the occiput rests upon a stone. Resistance is thus 

 offered to the forcing of the whole head downwards, and the com- 

 pression of the skull is limited by the amount to which the bed of 

 loose soil thrown or drifted in, immediately round it, is capable of 

 subsidence. 



I have lately been assured, however, that some of the Orkney skulls 

 in which this characteristic obliquity is clearly marked, have been 

 found in cists which have not been filled up with soil or sand. Such 

 instances, if authenticated, would suggest the solution, that in the 

 ease of a body slowly decomposing in a damp situation, the bones of 

 the head may become so thoroughly softened during the putrefaction 

 of the soft parts as to subside slightly. The subsidence would of 

 course be vertical, and its direction in reference to the form of the 

 skull would depend as before upon the position of the head at burial. 

 The process would be limited by the total decomposition and removal 

 of the soft parts, the skiill being left comparatively dry. 



XXXVIII. — On the G-eemikation" op Eeticulaeia itmbeina, 

 Er. By Frederick Currey, M.A., r.E.S. Sec. L.S. 



JReticularia umbrina is a fungus too well-known in this country to 

 require any introductory description or comment. It belongs to the 

 Myxogastres, a family which has lately attracted considerable interest 

 on account of the attempt of Dr. De Bary to transfer the plants 

 belonging to it to the animal kingdom. One of the most striking 

 peculiarities observed by that author was the peculiar mode of ger- 

 mination of the spores of many of the species. Instead of protrud- 

 ing in the first instance colourless filaments, as is the case with 

 almost all fungi in which germination has been observed, De Bary 

 noticed that in several of the Myxogastres, the contents of each 

 spore escaped in the form of a single zoospore. The plants men- 

 tioned by De Bary as those in which he had observed these zoospores 

 are the following, JEthalium septicum, Physarum albipes, Stemonitis 

 fusca and ohtusata, Arcyria punicea, Trichia ruhiformis, pyriformis, 

 and varia, Lycogala epidendron, and Beticularia umbrina. There 

 seems, however, some little doubt about the latter species, for in his 

 introductory notice in the Botanische Zeitung (1S5S), the plant was 

 called Beticularia maxima, and moreover the description of the spores 

 at p. 158 of the paper in Siebold and Kolliker's Zeitschrift does not 

 accord with the spores of Beticularia umbrina, as I have observed 



