1885.] PROF. LANKESTER ON THE HEART OF APTERYX. 239 



T. limula, Hilgendorf, from Senegambia, the postfrontal crest is 

 less distinctly developed near the lateral epibrauchial teeth, behind 

 which, in the males, are indications of two other teeth. 



7. On the Heart described by Professor Owen in 1841 as 

 that oi Apteryx. By E. Eay Lankester, M.A.^ LL.D., 

 F.E/.S., Jodrell Professor of Zoology in University 

 College, London, Fellow of Exeter College, Oxford. 



[Eeceived February 19, 1885.] 



When busy some three years ago with the examination of the 

 right cardiac valve of Ornithorhynchus and Echidna, I was naturally 

 anxious to examine the similar valve of Apteryx, which had been 

 stated by Sir Richard Owen to present a divergence from the 

 character which it usually presents in Birds, and instead of being 

 purely muscular as in all other Birds, to possess membranous arese 

 and chordae tendineae. Sir Richard Owen gives the following 

 account of this valve in his paper published in 1841, in the 'Trans- 

 actions ' of this Society (vol. ii. p. 272) : — 



" The principal deviation from the ornithic type of the structure of 

 the heart is presented in the valve at the entry into the right ven- 

 tricle (pi. lii. g. fig. 3). This is characterized in birds by its 

 muscularity and its free semilunar margin. In the Apteryx it is 

 relatively thinner, and in some parts semitransparent and nearly 

 membranous ; a process moreover extends from the middle of its 

 free margin, which process is attached by two or three short chorda? 

 tendinece to the angle between the free and fixed imrietes of the 

 ventricle. We perceive in this mode of concection an approach in 

 the present bird to the mammalian type of structure analogous to 

 that which the Ornithorhynchus, among Mammalia, offers, in the 

 structure of the same part, to the class of birds; for the right 

 auricular ventricular valve in the Ornithorhynchus is partly fleshy 

 and partly membranous. The dilatable or free parietes of the right 

 ventricle were about ^uth of an inch in thickness, those of the left 

 were ^ th of an inch thick." 



I was fortunately able to gratify my curiosity with regard to the 

 heart of Apteryx by the dissection of a specimen preserved in sj)irit, 

 which I owe to the courtesy of Mr. Cheeseman. 



I was not a little astonished to find that the right cardiac valve 

 of my Apteryx was totally different from that described b}' Owen, 

 and so far from presenting any membrane or chordae tendinese, 

 exhibited the normal structure of the right cardiac valve in birds ; 

 iu fact was a purely muscular lobe. I put the matter by at that 

 time, and was reminded of it a few weeks since by Mr. Beddard, 

 who told me that he had obtained a precisely similar result to my 

 owQ from the examination of a specimen of Apteryx which had 

 recently come into his possession. 



Mr. Beddard further told me that he had taken an opportunity 



