12 



PEOF. A. H. OAEEOD ON THE BRAIN 



The results arrived at by MM. Leuret and Gratlolet ^ tend strongly in the same 

 direction as those subsequently arrived at by Dr. Kreug ; nevertheless there is a com- 

 pleteness about the investigation of the last-named author which greatly increases the 

 importance of his work. 



As it is my intention on the present occasion to employ the nomenclature adopted 

 by Dr. Kreug, I cannot do better than introduce it by applying it to the description of 

 the typical Artiodactylate brain as represented by that author. 



Perhaps no nearer approach to this type can be given than that of the foetal sheep {Ovis 

 aries), 27-5 centimeters in length, figured by Dr. Kreug (figs. 1-3). Putting what is to be 

 seen in words, the small upward-directed j;yoce5S<<s acuminis {sac) of the Sylvian fissure is 

 just seen on the outer border of the superior surface of the cerebral hemisphere, along 



Fig. 1. 



Fig. 2. 



Fig. 3. 



Sheep's brain : fig. 1. Outer aspect ; fig. 2. Superior aspect ; fig. 3. Inner aspect. (After Dr. Kreug.) 



which latter surface the supra-sylvian fissure (ss) courses longitudinally nearly from end to 

 end, slightly concave outwards opposite the sylvian fissure. According to Dr. Kreug, 

 this fissure (ss) has three limbs ; but four seems to me to be the more correct number. 

 Of these one is anterior (ssa), the second superior (sss), and the third posterior (ssp). 

 The fourth, according to me, runs downwards (ssd) from the spot of origin of the poste- 

 rior limb. Typically, all these processes terminate freely. 



Next in importance, on the superior surface, is the coronal fissure (co), longitudinal 

 in direction, at no great distance from the middle line of the brain, and situated so far 

 forward that its posterior extremity is in front of the superior limb of the supra-sylvian 

 fissure (sss). It runs forward almost to the anterior margin of the hemisphere. 



A minor longitudinal (lateral) fissure (/) tends to divide the surface between the 

 posterior branch of the supra-sylvian fissure and the middle line of the hemisphere 

 into two equal parts. The praesylvian, diagonal, and posterior fissures, though they 

 appear on the superior surface, are so much better seen in the lateral view of the 

 brain that they will be there described. 



The inner aspect of the hemisphere presents, besides the hippocampal fissure (/(), a 

 long fissura splenialis (s/j), or calloso-marginalis, some distance from the superior margin, 

 curved concavely towards the corpus callosum, opposite the hinder end of which its 

 ' ' Anatomie Compareo du Systeme Nerveux,' Paris, 1S39-1857. 



