ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 75 



author finds that the air-chambers, which occur frequently in the 

 assimilative tissue, are clothed with an • epithelial sheath and arise 

 Bcbizogonously. He believes that they form respiratory chambers for 

 the plant, sucli as has been proved by Henckel for Chordaria. The 

 storing tissue consists of large parenchymatous cells, and has sometimes 

 intercellular spaces. Here may be seen the macropores of Wide. The 

 author cannot attribute to this tissue any mechanical role, which is 

 confined to the mechanical and assimilative tissues. Finally he dis- 

 cusses the genesis of the inner tissue, the " connective and sieve hyphae," 

 which together represent the conductive tissue. These cells are of 

 similar origin, and in the author's opinion represent all stages of mutual 

 transition. Sometimes their membranes are thickened, and then they 

 are able to form a mechanical tissue, which considerably strengthens 

 the stipes against stress. The membrane was found to consist of two 

 layers, which when stained with ClZnl showed an outer pectin layer, 

 and an inner cellulose layer. 



Hybrid form of Fucus.* M. Gard describes an interesting hybrid 

 between Fucks platycarpus and F. ceranoides, which occurs at Mimizan 

 in the Landes. The two species were found growing along the bank of 

 a stream which issues from the Anreilhan water. F. platycarpus is 

 found up to about SO metres above high watermark, and F. ceranoides to 

 about 120 metres. The two species are, however, abundantly mixed, 

 and in that region the hybrid is found. It resembles in dimensions 

 and colour the frond of F. ceranoides, but the receptacles are very 

 variable, not only in different plants but even in the same individual. 

 Some are branched, pointed and flattened like those of F. ceranoides, 

 some are thick and rounded like those of F. platycarpus. At first the 

 author found only male conceptacles, but later in certain leceptacles at 

 the extreme basal limit, he found some conceptacles with abundant 

 antheridia and a few rare oogonia. These latter were young or abnormal, 

 and of small dimensions. None were seen which had reached maturity. 

 On the other hand, the antheridia seemed quite normal. The herma- 

 phroditism of the hybrid was a character transmitted from F. platycarpus, 

 since all the specimens of F. ceranoides examined in the neighbourhood 

 were unisexual. The same hybrid was also found by the author in one 

 of the " courants ,, at Cap-Breton, Landes. It is not possible to deter- 

 mine at present the sexual. role of the parents. 



New Genera from the Malay Archipelago.!— A. Weber van Bosse 

 publishes preliminary diagnoses of new genera collected by herself in 

 the Malay Archipelago, on the ' Siboga ' Expedition. Full accounts and 

 figures will be given in her complete paper on the marine algas of the 

 region, which will appear later. The genera described in the present 

 note are : Bryobesia belonging to Derbesiaceae, Mesospora belonging to 

 Ralfsiaeeae, Exophyllum, of which the cystocarps are still unknown, but 

 which appears to belong to Rhodymeniaceae, Acanthockondria, Aneuria, 

 and Oligocladus all belonging to the Rhodomelaceae, ( 'halicostroma to 

 •Ceramiacere, and finally, a genus of uncertain position, Perinema. 



* Cornptes Rendus, cli. (1910) pp. 888-90. 



t Ann. Jard. Bot. Buitenzorg, s6r. 2, viii. (1910) pp. 25-33. 



