EOO LOGICAL AND BOTANICAL ASSOCIATION. 0J 



FRIDAY EVENING, JANUARY 21, 1859. 



Professor W. H. Harvey, M.D., F.R. & L.SS., M. R. I. A., 

 President, in the Chair. 



The Minutes of the previous Meeting having been read, were signed 

 by the Chairman. 



Professor J. Reay Greene read the following paper by Robert 

 Garner, F.L.S., Corresponding Member: — 



ON THE ANATOMY OF THE BRAIN IN SOME 8MALL QUADRT7PED8. 

 (WITH PLATE8 XXIII., XXIV.) 



The comparative anatomy of the brain — little studied in England (Pro- 

 fessor Owen having been almost the only labourer in the field) — has on 

 the Continent met with more attention. Witness the accurate researches 

 of Tiedemann, Desmoulins, and Leuret. As the importance of the sub- 

 ject to Zoology and Physiology cannot reasonably be doubted, the writer 

 of this short paper will make no further apology for offering the descrip- 

 tion of the brains of a few small but interesting quadrupeds, dissected 

 by himself. 



The two genera constituting that very peculiar division of quadru- 

 peds called Monotremes, similar in some respects, as far as the brain is 

 concerned, in others differ as remarkably. The Ornithorhynchus para- 

 doxus has a bony process in the interior of the skull, which separates the 

 right and left hemispheres. This is deficient in the Echidna hystrix. 

 In both the brain has much of the bird-like form, as is also seen in the 

 skull. The Echidna has well -developed convolutions to its brain ; that 

 of the Ornithorhynchus is only marked by the rather deep grooves of its 

 vessels. The former has the olfactory bulbs greatly developed; the 

 latter, much less so. The Echidna has not the little side lobules of the 

 cerebellum, which in the Ornithorhynchus are remarkable, occupying 

 cavities in the temporal bone, and encircled by the three semicircular 

 auditory canals ; whilst in the Echidna these last exist, but deep in the 

 solid bone. The Ornithorhynchus has the two posterior prominences of 

 the corpora quadrigemina very little developed, less than in any other 

 quadruped, as far as we know, making a gradation, therefore, to their 

 disposition in birds. Both have that peculiarity — general, it would ap- 



ZOOL. * BOT. SOC. PROC VOL. I. 2 H 



