282 DR. G. ELLIOT SMITH ON 



a series of coronal sections was carefully examined. But in none of these brains was it 

 possible to detect any histological features which could not be demonstrated much more 

 clearly and to much better purpose in the fresh brains of such Insectivores and E^odents 

 as are always available. Tor this reason I have not felt justified in giving illustrations 

 to represent histological facts, although my descriptions, and to some extent the 

 figures which accompany these descriptions, are largely based upon the results of 

 histological examination. 



When Professor Howes kindly suggested that I should undertake this investigation, 

 he very generously placed at my disposal all the Edentate brain-material which his 

 teaching-collection contained. This nucleus of material, ujwn which most of the 

 investigation was carried out, consisted of a very well preserved specimen of the brain 

 of an adult Orycteropus, as well as representatives of Tamanclua tetradactyla, Choloepus 

 didactijlus, and ChJamyclophonis truncatiis, in a somewhat less satisfactory state of 

 preservation. All these brains had been preserved in alcohol. 



Professor Max Weber, of Amsterdam, very generously gave me, on the suggestion of 

 Professor Howes, the brain of a young Bradypus tridactylus, which had been carefully 

 preserved in a chromic solution, so that it was available for histological work *. 



The magnificent collection of brains in the galleries of the Museum of the Royal 

 College of Surgeons in London inchides a valuable series of fifteen Edentate bi'ains, 

 and to these Professor Stewart kindly gave me free access. In this collection are 

 to be found representatives of the genera Orycteropus, Ilyrmecophaga, Tamandua, 

 Bradypus, Choloepus, Dasyp)us, Xemirus, Tutnsia, Tolypentes, and Munis. The Museum 

 also contains cranial casts of Choloepus and the extinct forms He gather ium and 

 Glyptodon. 



In addition to this, Professor Stewart very kindly placed the resources of his stock at 

 my disposal, and from this collection I obtained representatives of Dasijipus rillosus, 

 Bradypus tridactylus, a small Mauis of unknown species, and a number of partially 

 dissected brains, more especially of 3Iyrmecop)haga and Choloepus. 



Prom this it will appear that representatives of every genus except Cycloturus and 

 Priodon have been available for examination ; but, as the subsequent account will show, 

 we have imperfect data which, by comparison with other representatives of the same 

 families, will enable us to form a tolerably aiDproxiraate estimate of the configuration of 

 the brain in the Little Ant-eater and the Great Armadillo. 



Among the beautiful series of drawings which the late Professor Huxley bequeathed 

 to the Hoyal College of Science, there are sketches of the brains of Orycteropus, 

 Tamandua, and Dasypus sexcinctus, none of which liave been published. Professor Howes 

 has kindly allowed me to make use of these, and, as two of the sketches represent 

 the appearance in the fresh state of the actual brains of Orycteropus and Tamandua 

 whicli were used in this investigation, they proved of service in preparing rigures 

 3 and 25. 



* This brain is apparentlj- the second brai)i of Bradi/^ms whicli is referred tu in I'rofessoi' Max Weber's memoir, 

 " Vorstudien liber das Hirngewieht der Saugcfhiere," Sejiarat-Abdruck aus Festschrift fiir Carl Gegenbaur, 

 Leipzig. 18n(), p. 10!J. 



