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



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

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



i?'ig. 2. 



Ca'cuin 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 ^lycetes. It was difficult to 

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

 the thyroid, together vvith 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. 



Cieciim of Callithrix moloch, h 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 2i fissure 

 of Sylvius {Sy., fig. 5), behind which was a long anterior tetnporal 

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



