240 PROF. LANKESTER ON THE HEART OF AI>TERYX. [Mar. 3, 



of looking at Owen's specimen of the heart of Apteryx, which is now 

 in the Museum of the Royal College of Surgeons, No. 923 B. b. and 

 that it certainly differed altogether, as regards its right cardiac valve, 

 from an ordinary bird's heart, and from the ^/?<erya7-heart dissected 

 by him. Mr. Beddard remarked, as Owen had done himself, that 

 the valve in this specimen in the College of Surgeons was very 

 similar to the right cardiac valve of the Monotremata. 



It occurred to me that possibly Sir Richard Owen had made an 

 unfortunate mistake at the time of dissecting his Apteryx, and that 

 since he had at the same time specimens of Ornithorhynchus under 

 examination, side by side with the Apteryx, the heart of one of the 

 latter might, by the inadvertency of some assistant or attendant, 

 have been exchanged for the heart of the former. 



Accordingly on Feb. 18th I requested Prof. Charles Stewart to 

 allow me to remove from its bottle, and closelv examine the 

 specimen 923 B. b., labelled " Heart oi Apteryx australis" (so placed 

 and labelled, so far as I have been able to ascertain by inquiry, under 

 the direction of Prof. Owen). 



The figure in the Society's ' Transactions ' does not represent 

 the appearance of this heart, inasmuch as three musculi papillares 

 are figured, and are described as " chordae tendineae," whilst only 

 two (the great anterior and the right) are obvious in the prepara- 

 tion. That is, however, a matter of detail which Prof. Owen regarded 

 as liable to variation, since he says that two or three chordae tendinese 

 are present, and in his paper on Apteryx he speaks of having dis- 

 sected two specimens. 



On removing the heart from the bottle in Prof. Stewart's 

 presence, I was able to point out to him that the aortic arch of this 

 supposed heart of Apteryx has a sinistral and not a dextral flexure. 

 I also found that the auricles and the relatively small jugular sinus 

 are identical with that of Ornithorhynchus, and unlike the auricles 

 and large veinous sinus of any bird. I found, further, that the 

 arrangement of muscle and membrane in the right cardiac valve is 

 precisely (not only approximately) similar to that described by me 

 in Ornithorhynchus, and figured in the ' Proceedings ' of the Society 

 for 1882, pi. xl., and also in 1883, pi. iii. 



The shape of the whole heart, the shape of the right ventricular 

 cavity, and the markings of its surface (rudimentary columnae 

 carnese) are precisely of the same character as in the nine specimens 

 of Ornithorhynchus-hearta examined by me. 



I have no hesitation in stating that the heart, specimen No. 923 

 B. b., in the Museum of the Royal College of Surgeons, is not the 

 heart of an Ajyteryx, but the heart of an Ornithorhynchus paradoxus. 



This being the case, the discrepancy between the observations 

 made independently by Mr. Beddard and by me upon the structure 

 of the right cardiac valve of Apteryx, when compared with the 

 statements made forty years ago by Sir Richard Owen, is accounted 

 for. Sir Richard Owen did not examine the heart of Apteryx, but 

 by an accident occupied himself with the heart of an Omithorhyn-' 

 chus which he mistook for the heart of that bird. 



