8 



MR. W. F. R. WELDON ON CALLITHRIX GIGOT. [Jail. 15, 



it shows a slight dilatation. There is no appearance of an " appendix 

 vermiformis," such as was found in Callithrix moloch (cf. fig. 3). 



J?1g. 2. 



Ctecum of Callithrix gigot, h nat. size. 



Professor Flower suggested to me that the enormous depth of the 

 ramus of the mandibles in this Callithrix pointed to the existence of 

 some arrangement resembling that of Mycetes. It was difficult to 

 determine this point in a young female ; but the swollen condition of 

 the thyroid, together with the existence of a patch of ossification on 

 each side, seem to show the possible existence of a howling apparatus 

 in the male (see fig. 4). 



Fig. 3. 



C;eciiin of Callithrix moloch, £ nat. size. 



The lungs had a simple left lobe, the right lobe being divided by 

 shallow fissures into three, and bearing also a small accessory lobe. 



The brain was slightly more complex than that of C. moloch. 

 On the outer surface of each cerebral hemisphere was seen ajissure 

 of Sylvius (Sy., fig. 5), behind which was a long anterior temporal 

 fissure (a.t.) ; both being surmounted by an angular gyrus. There 



