768 report— 1884. 



SATURDAY, AUGUST 30. 

 The Section did not meet. 



MONDAY, SEPTEMBER 1. 



The following- Papers were read : — 



1. On the Value of Nerve-Supply in the Determination of Muscular Anomalies. 

 By Professor D. J. Cunningham, M.D. 



The author spoke of the muscula sternalis as a new muscle in man,' which had 

 no counterpart among animals. It was, according- to his experience, found more 

 frequently among females than males, while Professor Sheppard, of McGill College, 

 had, he learned, had three cases, all among males. 



2. On the Mutual Relation of the Recent Groups of Echinoderms. 

 By Professor A. Milnes Marshall, M.D. 



The author said that of these there were four groups, the common starfish, 

 brittle starfish, sea-urchins, and holothurians. The nerve-system was originally 

 derived from the skin. In some animals the nerve-system sank below, in others it 

 remained near the skin, the latter being in a more primitive condition than those 

 in which the nerve-system had sunk down. 



3. On the Fcetal Membranes of the Marsupials. By W. H. Caldwell. 



This paper gave an account of the development of the marsupial embryo, which 

 has been hitherto a riddle in biology. 



4. On the Progress of his Investigations in Australia. By W. H. Caldwell. 



5. An Attempt to exhibit Diagrammatically the several Stages of Ecolution 

 of the Mammalia. By G. E. Dobson, M.A., F.R.S. 



Plate IX. 



Since I had the privilege of hearing Professor Huxley read his paper on the 

 Application of the Laws of Evolution to the Arrangement of the Mammalia, I have 

 endeavoured to discover some mode of presenting his views, more particularly those 

 with respect to the Mammalia, in diagrammatic form, which might serve to convey 

 at a glance to the mind of the student the relative position of the various existing 

 groups of this class, not only to one another but also to the pre-existing classes from 

 which they have been derived, 



In the diagram which I now present I hope that not only has this object been 

 in a great measure attained, but that also some minor points, untouched in the 

 paper referred to, have been at the same time illustrated. 



To everyone who has read Professor Huxley's paper this diagram is, I trust, 

 self-explanatory ; to those who have not, the following notes may be acceptable. 



In this diagram the stage of evolution of the existing mammalian groups is 

 indicated by a series of concentric circles, so that at a glance the position of any 

 group with regard either to the hypothetical ancestors of the class, or to any other 

 group, is at once seen. 



These hypothetical ancestors, termed by Huxley Hypotheria, are included within 



