ii 





,ks; 



Jim 



■mm 



'68 



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. 

 JUj Professor D. J. Cunningham, M.B. 



The author tiprjke of the muscula sterimlis us a new muscle in man,'wliifli had 

 no counterpart iiinoii<r animals. It was, according to his experience, found uioro 

 freijuentlj' among females than males, while Professor Shepjjard, of McGill College, 

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



2. On th' Mutual Relation of the liecent Groups of Echinoderhi^. 

 Jji/ Professor A, Milnes MAKSnALL, M.D, 



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

 l)i'ittle starfish, sea-urchins, and holothiu'ians. The nerve-system was originally 

 derived from the skin. In sonu> animals the nerve-system sank helow, in otliersit 

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

 iu which the nerve-svstem had sunk down. 



3. On the Fc to I Merahranes of the Marsupials, '^y W, H. Caldwell. 



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

 has l)een hitherto a riddle in biology. 



4. On the T'rorjress of his Investigations in Australia. By W. H. Caldwell. 



5. An Attempt to exliihit Diagramma f icalJ i/ the several Staqes of Erolution 

 of the Mammalia! By G. E. DoiiSON, .1/.^., F.'li.S. 



Plate IX. 



Since I bad the privilege of liearing Professor Huxley read his paper on tiie 

 Application of the Laws of ]"-volution to the Arrangement of tiie Mammalia, I hine 

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

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

 at a glance to the mind of the student the relative position of the various exisfin;,' 

 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 ])resent T hope that not only has this object l)een 

 in a great measure attained, but that also some mimu* points, untouched in tlw 

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



To everyone Avho has read Professor Huxley's pa])er 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 h 

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

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

 group, is at once seen. 



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



