44 



pression. In the smaller specimen this is surrounded by a discon- 

 tinuous margin of the epidermis, with which substance, therefore, — 

 and, probably, from its having been shed, of a thickened or horny con- 

 sistence, — the caruncle had been covered. It is a structure of which 

 the upper mandible of the adult presents no trace, and Mr. Owen re- 

 gards it as analogous to the fcetal peculiarity of the horny knob on the 

 upper mandible of the Bird. He does not, however, conceive that 

 this remarkable example of the affinity of Ornilhorhynchus to the fea- 

 thered clas.s is necessarily indicative of its having been applied, under 

 the same circumstances, to overcome a resistance of precisely the 

 same character as that for which it is designed in the young bird, 

 since all the known history of the ovum of Ornilhorhynchus points 

 strongly to its ovoviviparous development. 



The situation of the eyes is indicated by the convergence of a few 

 wrinkles to one point ; but the integument is continuous, and com- 

 pletely shrouds the eyeball. In the absence of vision in the young 

 animal, strong evidence is afforded of its being confined to the nest, 

 there to receive its nourishment from its dam ; and this deduction is 

 corroborated by tlie cartilaginous condition of the bones of the ex- 

 tremities, and by the general form of the body : the head and tail are 

 closely approximated on the ventral aspect, requiring force to pull the 

 body into a straight line ; and the relative quantity of integument on 

 the back and belly shows that the position necessary for progressive 

 motion is unnatural at this stage of growth. 



Mr. Owen describes other external appearances of the young Orni- 

 Ihorhynchus, and then enters at considerable length into its anatomy. 

 The stomach is nearly as large in an individual four inches in length 

 as in the adult animal. In this specimen it was found filled with 

 coagulated milk, and no trace was visible, on the most careful exa- 

 mination, of worms or bread, on which, up to the time of his dis- 

 covery of the mammary secretion, Lieut, the Hon. Lauderdale Maule 

 had believed that this individual had been sustained. A portion of 

 this coagulated substance was diluted with water, and examined un- 

 der a high magnifying power in comparison with a portion of cow's 

 milk coagulated by spirit, and similarly diluted. The ultimate glo- 

 bules of the Ornithorhynchus' s milk were most distinctly perceptible, 

 detaching themselves from the small coherent masses to form new 

 groups : the corresponding globules of the cow's milk were of larger 

 size. Minute transparent globules of oil were intermixed with the 

 milk globules of the Ornithorhynchus. A drop of water being added 

 to a little mucus, it instantly became opake ; and its minutest divi- 

 sions, under the microscope, were into transparent angular flakes, en- 

 tirely different from the regularly formed granules of the milk of the 

 Ornithorhynchus. 



In passing in review the several viscera of the young Ornithorhyn- 

 chus, Mr. Owen observed on various physiological deductions which 

 might be drawn from them, and on the differences and resemblances 

 borne by them to the same organs in the ordinary viviparous Mam. 

 malia and in the Marsupiata. 



