180 Miscellanea. 



one dig a hole of more than two feet deep, in a very hard gravelly 

 soil, in less than ten minutes : during this operation the webs that 

 extend beyond the nails when the animal swims are retracted, and 

 the nails are exposed ; and from its attitude and action it would be 

 taken for a mole rather than a swimmer. As it burrows it uses its 

 tail, like a beaver, to beat the earth and consolidate the sides of the 

 burrow. 



The Ornithorhynchi are chiefly, but not exclusively, nocturnal; 

 they are most vivacious by night, swimming then with the velocity of 

 fishes, and moving about on land with rcmarliable agility: but the 

 female, when she has young ones in the nest, will leave them during 

 the noon-tide heats and swim about. 



With regard to the generative economy of the Ornithorhynchus I 

 may premise, that examination of the ovarium and of the ova, both 

 ovarian and uterine, had led me to the conclusion " that they were, 

 like the Marsupialia, ovo-viviparous ; and I conjectured that the 

 iitero-gestation would be more prolonged, and the allantois and 

 umbilical vessels probably more developed.* But the period of gesta- 

 tion remained to be determined, and the decisive proof of ovo-vivi- 

 pariiy, by the discovery of the foetus in utero and the examination of 

 its membranes, was a desideratum. This M. Verraux appears not to 

 have supplied, but he says : " The number of Ornithorhynchi which I 

 have possessed has perfectly demonstrated to me that this animal 

 does not lay eggs, as has been supposed, but that it is ovo-viviparous. 

 The ovaria, which form part of my collections, sufficiently prove this." 

 lb. p. 130. No doubt, had M. Verraux obtained the decisive proof 

 above referred to, viz. the impregnated uterus, he would have men- 

 tioned it.f He does not specify his physiological deductions from 

 the ovaiia, but they were probably those whicii led me to the same 

 conclusion in my memoir in the Philosophical Transactions for 1834. 

 In that memoir I had stated that " the season of copulation was pro- 

 bably at the latter end of September or beginning of October :" but 

 this point also remained to be determined by observation, together 

 with the manner of the coitus. The latter is thus described by M. 

 Verraux ; — " Pendant le raois de septembre je parvins a decouvrir 

 que I'accouplement avail lieu dans I'eau. Cache soigneusement sous 

 un cabane fabriquee expres, et au fond de Inquelie il nie fallait rester 

 des nuits entieres sans oser me mouvoir, c;ir I'Ornithorhynque est d'un 

 naturel excessivement mefianl, je pus suivre tons leurs nmuvements, 

 Le male, apres avoir poursuivi sa femelle plus d'une heure, finissait 

 toujours par I'araener au milieu des roseaux. La, se cramponant 

 solidement a I'aide de sou bee, il tenait fortement la peau du cou, 

 tandis que les eperous s'appliquaient sur la partie posteiieure. La 

 femelle, tout en se debattant energiquement, nageait et poussait des 



• Phil. Trans. 1634, p. 564. Art. Monotremata, CyclopasJia of Anatomy. 



f It is to the absence of this proof that Dr. Carpenter appears to refer, 

 where he remarks, in his excellent ' Principles of Human Physiolofry,' 1842, 

 p. 40, " No positive evidence has yet been obtained tiuit its young are born 

 alive." The minute size of the ovarian ovum, and consequently of ilie vitellus ; 

 the presence of small ova with a delicate chorion and without chalazjE orsliell, 

 in tiie uterine portion of tiie oviduct; the absence of any shell-forming por- 

 tion of the oviduct, — all are elements of a body of positive evidence in favour 

 of the ovo-«iviparity of the Ornithorhynclnts, whicli needs only tlie discovery 

 of the foetus in utero for decisive confirmation. 



