i«96. NOTES AND COMMENTS. 359 



certain stages, except in the oyster, in which the true teeth never 

 develop. 



From the point of view of the morphology of the hinge the 

 Taxodonts form a very natural and homogeneous group. 



The author's general conclusions are held over till his studies of 

 all the Pelecypod groups shall have been completed. 



A Big Fungus. 

 The visitor attracted to the Botanical Department of the British 

 Museum (Natural History) by the various additions and alterations 

 to which we have recently called attention, will be faced on entering 

 the gallery by a striking model of a huge specimen of the fungus 

 Hydnum erinaceiis, represented in the situation where it was found 

 growing. It does not bear much resemblance to the familiar 

 mushroom; nevertheless, the Hydneae belong to the same group of 

 fungi, namely, the Hymenomycetes ; but whereas in the mushroom 

 and its allies the spore-bearing layer (hymenium) is borne on gills on 

 the under surface of the fungus, in Hydnum it covers projecting 

 processes or teeth, which are well shown in this exhibit. The 

 specimen, of which this is a model, was presented to the museum by 

 the Hon. Mabel de Grey. It was found in the New Forest in the 

 hollow trunk of an old beech tree, in which sheltered position it had 

 grown to quite extraordinary dimensions, weighing 22 lb. 6 oz., though 

 always retaining the long teeth and the characteristic heart shape of 

 H. erinaceus. The exhibit reproduces very carefully the habitat and 

 appearance of the plant. 



Sexual Reproduction in Fungi. 



Owing to the questionable fate of the numerous nuclei which are 

 present in the sexual organs of the Phycomycetes, the exact nature of 

 the processes of fertilisation in this group of Fungi is of the greatest 

 interest. Our knowledge on this subject, however, has been in a very 

 unsatisfactory condition, due to the contradictory results obtained by 

 various observers. Mr. Wager has just worked out this point very 

 fully and satisfactorily in Cystopus candidiis. ("On the structure and 

 reproduction of Cystopus candidus, Lev.," Ann. of Bot., Sept., 1896.) 

 The result of his investigations is somewhat as follows. The oogonia 

 are formed by the passage of protoplasm with nuclei into expansions 

 of hyphse ; when a certain quantity has passed, the oogonia become 

 cut off by a transverse wall, and the nuclei can be distinctly made out. 

 They have exactly the structure of those of higher plants, and consist 

 of a nuclear membrane and network, and a nucleolus ; the average 

 number is about ninety. 



The structure of the antheridia is very similar ; they contain a 

 small quantity of protoplasm with from six to twelve nuclei. The 

 antheridia become closely pressed against the oogonia, and the latter 

 then go through the process of maturation. Their protoplasm ivith all 



