Notes, iv. 10. 239 



Ruminants four ; and a very large proportion of the polydactylous quadrupeds, as 

 already mentioned, numerous mammae. 



27. The number and position of the mammas are given correctly by A. in the other 

 instances ; but as usual (cf. Note 6) he is in error as regards the lion ; for though its 

 mammae are, as stated, abdominal, they are four, not two, in number. The lion 

 produces not unfrequently four, and occasionally even five or six, at a birth (cf. D. G. 

 iii. 10, 24). 



28. Cf. iv. 5, Note 2. 



29. i.e. in the direction from tail to head. This upward growth implies, he says, the 

 accumulation of nutriment in the part from which the growth proceeds, for otherwise 

 there would be no material for the growth ; and it is in this land of plenty that 

 the mammae are placed. In the human body the growth takes place in the contrary 

 direction (cf. Note 10); and the seat of plenty and location of the mammae is accordingly 

 at the opposite or pectoral end. 



30. Linnaeus counted the horse among those exceptional quadrupeds in which the 

 male has no teats ; but John Hunter discovered vestiges of them in the stallion. Possibly 

 what A. says may be true, and thus the discrepancy between these two modern 

 authorities explained. 



31. Cf. ii. 9, Note 3. 



32. Frantzius supposes that the exceptions meant are those groups of fishes, such as 

 the Teleostei, in which alone among vertebrates the external urinary and generative 

 apertures are perfectly distinct. I also suppose these to be the exceptions. I would, 

 however, point out, that it cannot be to the distinctness of these two apertures that A. 

 refers. For he expressly and repeatedly denies the existence of urinary organs, and 

 of course of urinary apertures, in fishes, and indeed in all ovipara excepting tortoises 

 (iii. 8, Note 3 ; iii. 9, Note i ; and iv. 13, Note 36). The whole passage is written 

 carelessly, and must be corrected by the light of other passages, such as the following : 

 "The generative fluid is discharged by the same opening as the residual matter ; when 

 an animal has residua of both kinds, fluid as well as solid, by the opening which gives 

 issue to the fluid kind ; for the semen is itself a fluid residuum ; but when there is no 

 fluid residue, by the opening which gives issue to the solid residue" (Z>. G. i. 18, 62). 

 See also the passage in iv. 13, Note 37. The exceptional condition, then, in these 

 fishes, to which I understand A. to refer, is the distinctness of the generative and anal 

 apertures. And I would take the passage to be as follows : "In all animals, with the 

 exception of the bony fishes, the generative fluid is discharged by the same aperture as 

 the fluid or the solid excrement ; in the vivipara by the aperture for fluid excrement ; 

 in the ovipara, where there is no fluid excrement, by the anus. " 



33. Hippocrates {KiihrCs ed. i. 551) had said, in partial anticipation of Darwin's 

 doctrine of pangenesis, that the semen was formed by contributions from all parts of the 

 parent's body ; and he explained on this hypothesis the resemblance of the offspring 

 to the parent, which extended occasionally even to accidental or acquired peculiarities 

 of structure. This opinion is combated by A. (Z?. G. i. 17-18), who insists, among 

 other arguments, that it would imply that the semen was a product of dissolution or 

 decay ((rhvf(\\is), which is clearly inadmissible. He argues that the semen can be 

 nothing else in substance than the surplus or residue of sound nutriment, which, after 

 conversion into blood, has not been required for growth. This, he says, explains 

 why no semen is formed either when the growth is active, as in childhood, or when 

 the power of concocting nutriment is small, as in old age or sickness ; and also why 

 those animals, whose surplus nutriment is turned into fat, are not prolific (ii. 5, Note 9). 



