Prof. Owen on the Oniitkorhynckus. 319 



mouvoir, car FOrnitkorkynque est (Tun naturel excessivement 

 mefiant, je pus suivre tous leurs mouvements. Le male, apres 

 avoir poursuivi sa femelle plus d'une keure, finissait toujours par 

 Famener au milieu des roseaux. La, se cramponant solidement 

 a Faide de son bee, il tenait fortement la peau du cou, tandis 

 que les eperons s'appliquaient sur la partie posterieure. La 

 femelle, tout en se debattant energiqueinent, nageait et poussait 

 des cris plaintifs qui offrait quelques rapports avec ceux d'un 

 petit cockon, et qui allaient toujours augmentant : Faccouplement 

 durait cinq ou six minutes, ensuite les deux auimaux jouaient 

 ensemble pendant plus d'une keure." lb. p. 130. 



We kave seen tkat M. Verraux draws kis conclusions from tke 

 ovaria of tke female, tkat ske is ovo -viviparous. Tke period of 

 gestation kas yet to be determined. I kave calculated it at about 

 six weeks, judging from tke size of tke uterine ova in a female 

 killed December 8tk in tke Murrumbidgee river, and from tkat 

 of young ones found in tke nest in tke banks of tke same river 

 two montks afterwards. M. Verraux, alluding to tke kabit of 

 tke female to quit ker burrow during tke keat of tke day, says 

 tkat tkis occurs — " lorsqu'elles ont des petits, c'est-k-dire depuis 

 novembre jusqu'en Janvier," ib. p. 132 : meaning, tkat ske kas 

 young ones in ker nest at tkat time. He states tkat Ci a gentleman 

 in Tasmania, Dr. Casy, kad discovered (but tke date is not given) 

 two nests of tke Ornithorhynchus, one witk a single young one, tke 

 otker witk two ; tkey were naked, but vigorous in proportion to 

 tkeir size. Tkeir beak did not at all recall tke form of tkat of tke 

 adult, but was skort, broad and tkick, and could embrace in tkat 

 state tke mammary areola concealed by tke kairs of tke motker." 

 Tkis accords witk tke description and figures of tke beak of tke 

 young Ornithorhynchus given in my memoir on tke young Orni- 

 thorhynchus in tke 1st vol. of tke Zoological Transactions ; wkere 

 it is also skown, tkat " tke tongue, wkick in tke adult is lodged 

 far back in tke moutk, advances in tke young animal close to tke 

 end of tke lower mandible ; all tke increase of tke jaws beyond tke 

 tip of tke tongue, wkick in tke adult gives rise to a form of tke 

 moutk so ill- calculated for suction or application to a flattened 

 surface, is peculiar to tkat period, and consequently forms no ar- 

 gument against tke fitness of tke animal to receive tke mammary 

 secretion at an earlier stage of existence. Tke disproportionate 

 breadtk of tke tongue is plainly indicative of tke importance of 

 tke organ to tke young animal botk in receiving and swallowing 

 its food. Tke mandibles are surrounded at tkeir base by a tkin 

 fold of integument, wkick extends tke angle of tke moutk from 

 tke base of tke lower jaw to equal tke breadtk of tke base of tke 

 upper one, and must increase tke facility for receiving tke milk 

 ejected from tke mammary areola of tke motker." Tke arrange- 



