400 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



its development, the egg-cell has to get rid of its male 

 element, and the spermatozoon of its female element. We 

 have just seen that Minot holds the same view, but while 

 the latter considers tlie polar bodies as the homologues of 

 spermatozoa, and, therefore, as male cells, v. Beneden believes 

 the polar bodies not to represent cells, but male nuclear 

 structures (chromatin-scgments) got rid off by a process of 

 pseudokaryokinesis. This pseudokaryokinesis would then 

 render the nucleus of the egg-cell of necessity unisexual and 

 female, and such a nucleus containing only one sexual 

 element, and unable to undergo division, he termed a pro- 

 nucleus. 



The nucleus being only a pronucleus, will further, of 

 necessity, render the egg-cell an incomplete cell, incapable 

 of division (gonocyte femelle), till by the reception of a male 

 pronucleus the pronucleus of the egg-cell has regained its 

 full power, and the faculty of undergoing division.* 



Brooks t seems to hold that reproductive elements are the 

 result of a division of physiological labour in different direc- 

 tions, but how this differentiation took place, has not been 

 defined. 



Ealph I defines a male as a less nutritive and therefore 

 smaller, hungrier, and more mobile organism ; the female as 

 the more nutritive and usually more quiescent organism, in 

 which metabolism is more marked than in the male. 



Geddes and Thompson § believe a fundamental difference 

 to exist between " the nutritive, vegetative, or self -regarding 

 processes within the plant or animal, as opposed to the repro- 

 ductive, multiplying, or species-maintaining processes." As 

 the nutritive changes may be resolved into constructive 

 (anabolic) and destructive (katabolic) metabolism, and as 

 " anabolism " and " katabolism " stand in continuous anti- 

 thesis, and as furtlier the sexual organisms (female and male) 

 also show an antitliesis, in as far as the female is inclined to 

 passivity, while the male is inclined to activity, a parallel- 

 ism between the processes of nutrition and reproduction is 



* For a full account of the; variou.s tlifoiies, see the fidiiiiralile paper by 0. 

 Ileitwi-,', Ver<,'Icicli d. Ei und Saincidiild. b. Neinatoden. (Aicliiv. 1'. Mikios- 

 cop. Aiiat. xxxvi. ]>. ]), where these theories have also been criticised. 



+ ^\'. K. I'.rooks, Tlie Law of Ilciedity, lialtiinore, 1883. 



X W. H. Ralph, l;iolo;,dsche I'robJenie, Leij.zi^', 1884. 



§ The Evolution of Sex. The Contemporary Science Series, 1889. 



