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February 12, 1833. 

 William Yarrell, Esq., in the Chair. 



A letter from M. GcofFroy-Saint-Hilaire, For. Memb. Z.S., was 

 read, consisting of reflections on the communication respectfng the 

 Ornithorhynchus, made by Dr. \Veatherhead to the Committee of 

 Science and Correspondence, on Septemberll, 1832, and published 

 in the Procecdings, Part II. p. 145. With this communication M. 

 GeofFroy-Saint-Hilaire was only partially acquainted, by the extracts 

 from it given by Mr. Pwen (vvith some observations upon them,) as 

 an Appendix to his Paper on the Mammary Glands of the Orn'Uho. 

 rhi/nchus paradoxus,\')uh\ished in the Philosophical Transactions for 

 1832 : be requests to have a Hteral copy of the communication. 



He recalls attention tothehistory ofour knowledge of the sexual 

 organs of Ornithorhyhclnis ; refers to M. Meckel's discovery of a 

 gland, situated under the integuments of the ahdomen of the female, 

 and considered by him as mammary, and to his own subseąuent ob- 

 servations on this subject, in which these glands are regarded as 

 analogous to the structure that surrounds the true mammary glands 

 of the Shretvs ; and hints at the probability that M. Meckcl may 

 not, in 1833, entertain the šame ideas vvhich he expressed in 1826. 

 M. GeofFroy-Saint-IIilaire repeats some of the most striking pecu- 

 liaritics of the organs of reproduction : 1, the existence of a uterus 

 and vagina in a statė of atrophy, which he has repeatedly represented 

 under the nameof a little indistinct organ, the utero-vaginal canai ; 

 2, the non-continuity of the urinary bladder to the ureters ; 3, the 

 interposition, when in action, of the genital organ betvveen the folds, 

 &c. ; and, referring to his published accounts of the sexual anomaly 

 in all its details, reproduces the concJusion to which hehas been led 

 by his observation of these parts. The organization, he finds, is 

 that of a Reptile; now, such as the organ is, such mušt be its func- 

 tion ; the sexual apparatus of an oviparous animal can produce no- 

 thing bu t an egg. 



The statement that a milky fluid has been observed is one vvhich 

 especially attracts M. (ieoffroy-Saint-Hilaire's attention : he is 

 anxious to know the details of this observation. Supposing it esta- 

 blished, rather than believe in a secretion of real milk from long 

 cellular cceca, of vvhich Meckel's gland is composed, (vvhereas, he 

 States, it can be secreted only from lactiferou.s ganglia,) he would 

 be disposed to think that this gland might secrete carbonate of soda 

 [lime ^■'J, the earthy matter of vvhich egg-shells are composed. This 

 would be extraordinary, he admits ; but what is thcre about the or- 

 ganization of the Monot}-einata that is not extraordinary, or, in other 

 vvords, different from vvhat we find in the Mammalia ? This addi- 

 tional anomaly seems to lead to its necessary consequence, he re- 

 niarks, and an hypothesis whicii suggests the necessity of furthcr 



