Prof. Owen on the Ornithorhynchus. 321 



male Ornithorhynchus, the evidence of its function was summed 

 up in my article Monotremata as follows : — u An objection to 

 the theory of the spur and gland being a defensive apparatus is 

 their absence in the female. Since then this apparatus forms a 

 sexual character, it may be presumed that its function is con- 

 nected with that of generation. Whether the spur be a weapon 

 for combat among the males, — or, like the spiculum amoris of 

 the snail, be used to excite the female, the injected secretion 

 being an additional stimulus, — or whether the spur be mecha- 

 nically useful in retaining the female during the coitus, — are 

 conjectures which must be verified or disproved by actual ob- 

 servation *." 



M. Verraux states: — "Quant aux crochets qui arment les mem- 

 bres posterieures du male, et qui, chez la femelle, sont rudimen- 

 taires, ils n'ont d'autre destination, d'apres moi, que de main- 

 tenir la femelle pendant Facte de copulation." — " Les experiences 

 souvent reiterees h diverses epoques m'ont atteste que ces cro- 

 chets n'avaient rien de nuisible. J'ai meme observe qu'en tra- 

 cassant Fanimal, jamais il ne cherchait h s'en servir comme 

 moyen de defense," ib. p. 133. This precisely accords with what 

 Mr. G. Bennett has recorded in the Zoological Transactions, vol. i. 

 p. 236. 



Upon the whole then, M. Verraux's evidence goes to confirm 

 the ovo-viviparous theory of the Ornithorhynchus, determines the 

 season and mode of coitus, agrees with the calculations previously 

 made as to the period of gestation, establishes the function of 

 the mammary glands, and describes two modes by which the 

 young acquire the lacteal secretion : it also demonstrates one use 

 of the perforated spurs of the male, though that of the secretion 

 which they emit is still conjectural. The chief points then that 

 remain to be determined by actual observation are — 

 1st. The precise period of utero-gestation. 

 2nd. The nature of the membranes or other structures de- 

 veloped for the support of the foetus during gestation, and the 

 order of their appearance. 



3rd. The exact size, condition and powers of the young at the 

 time of birth. 



4th. The period during which the young takes the lacteal 

 nourishment. 



5th. The age at which the animal attains its full size. 



The most important desideratum for the physiologist is the 



impregnated uterus of the Ornithorhynchus at different periods. 



Such specimens are indispensable for the determination of the 



second point. It would seem that they might be obtained without 



* Cyclopaedia of Anatomy, vol. iii. p. 407. 



