152 EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 



caused by the situation in which they are developed and by the excess 

 or the want of action of air, light, humidity, and temperature. 



He distinguishes four forms of Mycelium : 



L The Filamentous or Nematoid Mycelium, composed of white or 

 coloured chambered filaments, anastomozing with each other; these 

 form the genera Athelia, Hupha, Himantia, &c. 



2. The Membranous or Hymenoid ; exhibiting membranes of a greater 

 or less degree of thickness known by the names of Racodlum and 

 Xylostroma. 



3. The Tuberculous or Scleroid, the principal subject of this me- 

 moir. 



4. The Pulpy or Malacoid, which is fleshy, soft, and found in the 

 genera Phlebomorpha and Mesenterica. 



The following are the conclusions to which he arrives : The greater 

 number of Fungi proceed from a Mycelium which appears to be a par- 

 ticular kind of vegetation or evolution of spores. This Mycelium pre- 

 sents itself under four principal forms ; it is often long lived, and vitality 

 can be suspended in it for a greater or less time, and made to appear 

 under the influence of favourable circumstances. Endowed with this 

 power, it is manifest, nature has reserved it as a means of reproduction 

 and preservation of the species. 



The genus Sclerotium is but one of these forms ; it ought not there- 

 fore to be considered a genus. It is the same with Acrospermum, Rhi- 

 zoctonia, Fibrillaria, Himantia, Athelia , Hypha, Rhizomorpha, Mesente- 

 rica, &c. 



All Fungi, and every myceloid tissue, under whatever aspect it pre- 

 sents, are but individuals either in the act of growth or arrested in their 

 development. 



These productions are far from being perfectly known. The time has 

 not yet arrived to efface them from the history of Fungi ; on the con- 

 trary, they merit more than ever the attention of Botanists because they 

 are natural experiments of which unexpected results may be obtained 

 on the reproduction of Fungi. 21st March, 1842. 



[From the Annales des Sciences Naturelles, 1841.] 



Milne Edwards on the existence of Sexes in JEquorea violacea. In this 

 species, as in others of the same genus, hitherto described by zoologists, 

 there is to be found at the inferior surface of this animal of the family 

 of Medusa, called Cryptocarpia, a number of membranous lamellae, ar- 

 ranged in a radiated manner around the stomach, and corresponding to 

 the canals described as passing from that viscus to the border of the 

 expansion (ombrelle) ; they occupy however only about three quarters 

 of their length, as they do not commence immediately at the margin of 

 the mouth, and terminate at a sufficiently distinct distance from the 

 border of the expansion (ombrelle). Two of these lamellae are sus- 

 pended in a parallel manner below, each of these tubes similar to a 

 riband folded upon itself, as would make it appear double. Seventy- 

 four of these double radiated lamellae may consequently be counted, 



