OF THE SKXKS. 309 



explained. The usual identity of the sex of twins still shows 

 only Nature's general plans, and the frequent infecundity of 

 twins of different sexes only that general plans have been some- 

 what thwarted. 



The sex of the offspring would appear determined by the fe- 

 male rather than by the male. Mr. Knight has observed that 

 individual cows, &c. however various the males, produce one sex 

 rather than the other, so that he has with tolerable certainty pre- 

 dicted the number of male and female young j while nothing 

 similar was ever observable in regard to his bulls, rams, &c. 

 Even the external appearance and the habits of brutes and vege- 

 tables, he has found much more, and sometimes altogether, in- 

 fluenced by the female. The quantity of pollen employed in the 

 fecundation of female plants, he found of no importance in this 

 respect.* 



(B) The form as well as the texture of the female is more 

 delicate : her surface has no muscular protuberances, but is beau- 

 tifully rounded ; her legs therefore have no calves, but, like the 

 arms and fingers, gently taper ; her feet and hands are small ; 

 her stature one sixth shorter than that of the male ; her neck 

 longer. From the smaller stature and the greater size of the 

 abdominal and lumbar regions, it follows that the middle point 

 which lies at the pubes in the male, is situated higher in the 

 female. Her abdomen is more prominent and rounded, and hep 

 shoulders stand less forward and distant from the trunk. Her 

 thighs are more voluminous and distant from each other. 



(C) The greater capacity of the female pelvis, which contains 

 the chief organs of generation and affords a passage for the 

 child, arises from the greater expansion of the ossa ilei, the 

 larger angle of the junction of the ossa pubis, and the greater 

 concavity and breadth of the os sacrum : the os coccygis like- 

 wise is more slender and moveable. The clavicles are less bent ; 

 the thorax more projecting, whence deeper, although narrower 

 and shorter ; the sternum shorter and broader ; the cartilago 



* Philos. Trans. Vol. 99. 



