CONTENTS. Xlll 



Page 

 Observations on Generation. 



Ou the distinctive Characters of the Sexes 184 



Sexes, distinctive characters of, inappreciable at early age 186 



Sexes, distinctive characters of, are deviations from a common type .... 186 



Sexes, relative degree of deviation in the two 186 



Generation, physical causes of pleasure in the act of 186 



Generation, mental influence over the act of 187 



Sexes, their relative pugnacity when in heat 187 



Seasons for Breeding 187 



Seasons for Breeding, influence of heat on 187 



Testes, relation of vesiculse seminales to size of 187 



Testes, their shape 188 



Testes, exit from abdomen in Brutes 188 



Testes, condition of tunica vaginalis of, in Brutes 188 



Testes, origin of vessels of 188 



Prostate, its relative position in Man, as deducible from disease 188 



Seminal reservoirs in the Fowl and Shark 188 



Semen, its smell and taste 189 



Mucus of Urethra 189 



Penis, cause of erection 189 



Penis, its sympathy with Bladder 189 



Penis, its muscularity in the Horse 189 



Ovaria, persistent in Vertebrata, except Osseous Fishes 190 



Ovaria, temporary also in Crustacea and some Insects 190 



Oviducts, in ' Ovipara' 191 



Oviducts, in ' Vivipara vera/ or ' Fallopian tubes' 191 



Uterus, where double 191 



Uterus, its functions 191 



Uterus, is the seat of the menstrual discharge 192 



Uterus, round ligaments of, analogous to cremaster 192 



Vagina, peculiar to ' Vivipara vera' 192 



Vulva and Pudenda 192 



Clitoris , 193 



Menses, source of 193 



Coitus, why debilitating 193 



Coitus, difference of desire for, in male and female 194 



Coitus, exemplified by male Ass and female Zebra 194 



Superfcetation in the Goat 195 



Superlactation in the Negress 195 



Motion of Foetus in Utero 195 



Modes of materno-fcetal communication 196 



Foetus and its membranes in the Uterus Bicornis 196 



Impregnation, experiments on Sows 197 



Impregnation, experiments on an Ass 199 



Progress and Peculiarities of the Chick 1 . 

 Of the Egg of the Bird 199 



1 [The original MS. accompanied the Hunterian drawings of the development of 



