878 RECORD OF CURRENT RESEARCHES RELATING TO 



nucleus, nuclear disk, " suns," &c. His observations, therefore, tell 

 strongly against Brandt's amceboid theory of nucleus-division, ac- 

 cording to which there is no real differentiation of the nucleus, the 

 fibres described in it being merely folds in its membrane, and the 

 " suns " at its poles, radially arranged nuclear processes or pseudo- 

 podia. 



Prizes for Life-histories of Entozoa. — The council of the En- 

 tomological Society of London are authorized by Lord Walsingham 

 and other gentlemen interested in the diseases of our native game- 

 birds to offer to public competition the following prizes : — 



501. for the best and most complete life-history of Sderostoma 

 syngamus Dies., supposed to produce the so-called " gapes " in 

 poultry, game, and other birds ; 501. for the best and most complete 

 life-history of Strongylus pergracilis Cob., supposed to cause the 

 grouse disease. 



No life-history will be considered satisfactory unless the different 

 stages of development are observed and recorded. The competition 

 is open to naturalists of all nationalities. The same observer may 

 compete for both prizes. Essays in English, French, or German to 

 be sent in on or before October 15, 1882, addressed to the Secretary 

 of the Society, Chandos Street, Cavendish Square. 



Development and Metamorphoses of Taeniae.* — M. P. Megnin 

 now gives a fuller account of his observations than that which ap- 

 peared in the ' Comptes Eendus.'j He expresses the opinion that the 

 armed Tcenice, or those which are provided with sj)ines, are forms 

 which exhibit a suppressed development ; it is, however, to his remarks 

 on the polymorphism of these forms that we now wish to direct 

 especial attention. As he very justly observes, the existence of two 

 adult forms developed from the same cestoid worm ai:)j)ears to be very 

 remarkable ; to remove any difficulty in accepting the correctness of 

 his statements, he directs attention to the polymor{)hism which obtains 

 [as Elders has shown] in Nereis Dicmerilii and Heteronereis fiicicola, 

 of which one is small, agile, and free swimming, and the other large, 

 slow, and bottom-dwelling ; similar examples may be taken from 

 among the Arachnida, and it is concluded that polymorphism is the 

 rule in the lower animals, and that this polymori^hism is always the 

 result of the influence of the surrounding medium, or is efiected by 

 certain special conditions of existence. In the particular case now 

 under investigation, the cause is pretty evident ; when the " vesicular 

 worm " passes into the Carnivore it finds itself in an intestine, the 

 contents of which are in a state of continual movement so that the 

 feeble scolex has need of all its hooks and suckers to fix itself to the 

 wall ; but, in the Herbivora, it can pass into a more retired position, 

 and here the hooks are altogether useless. 



Nematodes in the Caves of Carniola.| — Dr. Gustav Joseph, of 

 Breslau, gives a brief account of his researches on the hitherto little- 



* ' Journ. Anat. et Phys.' (Eobiu), xv. (1879) p. 228. 



t See this Journal, ante, p. 162. 



t ' Zool. Anzeiger,' ii. (1879) p. 275. 



