Mr F. E. Becldard on the Ovary of Echidna. 355 



to the fact that these mammals lay eggs; he stated that 

 specimens of the eggs had been sent to London. A few 

 years later (1829) Geoffroy St Hilaire communicated a paper 

 to the French Academy upon the same subject. This naturalist 

 described and figured the egg of Ornithorliynchus, and made 

 use of this fact in its life-history as an additional argument 

 against including the Monotremata among the Mammalia. 

 It was the opinion of Geoffroy St Hilaire and also of Lamarck 

 that the Monotremata should form a distinct class of the 

 Vertebrata, equivalent to, and not included in, the Mammalia. 



I need not recapitulate here the numerous other papers 

 and notices respecting the eggs of the Monotremata, but 

 refer the reader to Mr Spencer's review for further details on 

 the subject. There are several papers, however, which have 

 appeared since, and have not therefore been referred to in 

 the review from which I have quoted. One of them is by 

 Sir Eichard Owen, who has re-described^ and figured the 

 generative organs of a female example of the Australian 

 Ant-eater; both the uteri of this specimen contained a " col- 

 lapsed ovum," which was shown to be entirely unconnected 

 with the walls of the uterus. 



A recent number of the Zoologischer Anzeiger ^ contains a 

 paper, by Dr W. Haacke, on the ova of Echidna, and the 

 same gentleman, on Thursday, January 8, communicated an 

 account of the discovery of this fact, together with observa- 

 tions on the pouch and the mammary glands of the male, to 

 the Eoyal Society of London, which are not, of course, pub- 

 lished as yet. In the paper in the Zoologischer Anzeiger, Dr 

 Haacke describes having found an egg in the pouch of an 

 Echidna " about 2 mm. long, and having a shell, as in many 

 reptiles, of a parchment-like consistency." 



Mr Caldwell's telegram to the British Association con- 

 tained another statement, and one of greater importance — 

 viz., that the ova of the Monotremata are meroblastic ; and 

 this is the real essence of the discovery. Unlike what is 

 found in other mammalia, the ova of the Monotremata only 

 undergo partial segmentation. The large ovum is furnished 



1 Ann. and Mag. Nat. Hist, Dec. 1884. 



2 Jahrg. vii., No. 182, Dec. 1884. 



VOL. VIII. Z 



