Material for the Study of Ruminants. 



39 



is seen in the figure (fig. 23 a) to form a rather deep depression cor- 

 responding to sulcus coronalis from which a short branch turns laterally 

 downwards but the main sulcus continues forwards and downwards 

 finally dividing in two short branches. This arrangement does not 

 seem to agree fully with the corresponding one in foetal specimens 

 of sheep and ox (Krueg). On the other hand it offers some likeness 

 with the brain of Tragulina and some deer in which sulcus coronalis 

 and suprasylvius are connected. On top of the prosencephalon of the 

 CejjhalopIuis-îoGtus is seen an almost straight furrow which according 

 to Krueg's terminology should be sulcus lateralis and which has about 

 the same situation as in foetal specimens of sheep and ox. Just at 

 the border between the upper and median surface of the prosencepha- 

 lon extends a furrow beginning at the hind-end of the organ on the 

 posterior surface and running as has been mentioned. The posterior 

 portion is rather better visible from above than the anterior fourth but the 

 foremost end curves up again on the upper surface not far from the 

 anterior end of the foremost fourth of the prosencephalon. This furrow 

 must correspond to sulcus splenialis and its situation as described above 

 is of great interest because is it quite different from that in Ovis and 

 Bos in which genera the said sulcus is confined to the median sur- 

 face even in foetal stages. According to Retzius this latter is the 

 case in the adult Ovibos and according to Krueg in Ovis, Ga.pra, B.uj>i- 

 capra and other Oavicornia as well and also in the Cervicornia which 

 he has investigated. But on the other hand Gazella dorcas »Tragulus 

 sp.» and Moshus moschiferus have this furrow visible from above as in 

 the foetus of Oephalophus melanorhoeus. This is no doubt an important 

 feature indicating the Cephalophus to be rather primitive in this respect. 



The brain of a more advanced stage (stage f.) is still more 

 badly preserved, but the following can be observed. The general 

 shape of the whole organ is very elongate. The length of each he- 

 misphere is about 44 mm. measured in a straight line and in the same 

 way the greatest width of the dorsilateral surface is only about 23 

 mm. Each hemisphere has thus the shape of a section of a pear. 

 This elongate shape may also be regarded as a primitive characteristic. 

 Rhinencephalon is very large. Each of the bulbi projects about 8 mm. 

 in front of the prosencephalon. The furrows of this stage have pro- 

 bably attained almost the same development as in the adult. 



The fissura Sylvii is represented by a deep vertical cleft cor- 

 responding to the processus acuminis of Krueg. Below, it divides as 



