29 



; " The epigastric artery is divided into two principai branches ; one 

 passing towards the median line to supply the maramaiy glands ; the 

 other ramifying external]y and performing the šame function with re- 

 gard to the odoriferous glands. The šame structure exact]yis presented 

 by the ventral glands ofthe Ornithorhy neims, two characters excepted, 

 ■vvhich do not militate against the determination and analogy assigned 

 to them : viz. a much more extehsive development, and two secretory 

 orifices instead of one, as in the Shreivs. I explain this difference by 

 the atrophy and entire suppression of the internal epigastric branch. 

 This branch being annihilated, there is no formative vessel, and con- 

 seąuently no apparatus produced, — no mammary gland ; but, on the 

 other hand, the \vhole arterial alimentation passing more excentrically 

 by means of the single terminai branch, the apparatus to which this 

 branch is distributed is proportionally enlarged. This shows \vhy and 

 how the odoriferous glands have reached, in the Monotremata, their 

 maximum of development. Where the apparatus becomes more con- 

 siderable, the function is so much the more powerful, and the mucus 

 secreted mušt in fact exist in such quantity in the Monotremata, that 

 its effusion may become a fact susceptible of observation. 



" I should not be surprised, if this mucus, more abundant and more 

 substantial in the Monotremata, became the nutriment of the young 

 after their hatching. The Monotremata \vould act, in this respect, 

 likę some aąuatic birds •vvhich conduct their young after hatching to 

 the water, and assist them in their substantation. The maternal in- 

 stinct Avonld lead the female Ornithorhynchus to effect the contraction 

 ofthe gland, •which is possible by the efForts of \\\e panniculus carnosus 

 and the great obliąue musele, between the fibres of ■vvhich the gland is 

 seated, and thus to procure for the young, at several periods ofthe day, 

 by wayofnutriment,an abundant supplyof mucus. Ifthis educationis 

 carried on in thewater, wherewe know,by the history of the generation 

 of frogs and the nutrition of their tadpoles, that the mucus combines 

 "vvith the ambient medium, becomes thick, and supplies an excellent 

 nutriment for the early age of these reptiles, vfe shall understand the 

 utility of the ventral glands of the Ornithorhynchus, as furnishing a 

 source of nutriment for the young of these animals, — for young ovipara 

 newly hatched. Wlien we meet ■vvith such curious organic conditions, 

 we do not attempt, by a truly retrograde march, to thro^vv back -v^^eU 

 averred difFerential facts, decidedly acąuired to science, by means of 

 a forced assimilation, among other facts peculiar to the class of Mam- 

 maliū; but on the contrary Ave are under the necessity of placing the 

 Monotremata further ■vvithin the limits of oviparous animals. 



" At the other extremity of the scale of beings, where the fishes are 

 placed, we meet with a gland secreting mucus, extending along the 

 sides from the head to the tail. Ascendjng the scale, we see it sepa- 

 rate into fractions ; some Reptiles, and among others the Salamanders, 

 have it large and forming a continuous band, as in Fishes : vie have 

 said in what statė it is found in the Monotremata." 



In a postscript, dated February 19th, M. Geoffiroy statės that at a 

 Meeting of the Academie des Sciences on the previous day, M. de 



