( 364 ) 



a few blooil-vessels, but these ended in the frennm for whose nonrishment they 

 are clearly intended ; they are not blood-vessels on their way to the caecal wall. 



The large intestine has no bands upon its snrface or the corresjionding 

 sacculations ul' its walls. In this the present ajjrccs with other sjiccies of the genus. 



The liver of Callitluix torquata is illustrated in Plate XL, fig. '2. So far 

 as the material is known, it appears that this organ shows differences in different 

 species. I am able to sujiplement my own figure of C. torquntu by a co]iy of a drawing 

 of the liver of ('. jiersonata (Plate XL, fig. 1) made by Mr. Forbes. Professor 

 Weldon has illustrated the liver of C. gigot. The liver of the species which forms 

 the subject of the present communication has a larger right central lobe than have 

 either of the two other species. This lobe is moreover divided into two at least 

 partly. The gall-bladder does not come anywhere so near the edge of the lobe 

 as it does in ('. gigot, and in this latter point the liver of C. prrsonata agrees most 

 nearly with that of C. torquata. Professor Weldon has not figured a curious little 

 flap of liver tissue which arises from the left central lobe and partly overlaps the 

 gall-bladder. This small almost detached bit of the left central lobe occurs, but 

 appears to be less marked, in ('. jjeisonata. It occurs also in Brachgurus rit^ji- 

 curif/iis and in Pithecia albinasa ; but I could not find it in Lagothrix. 



The right lateral lobe is perfectly entire ; there are no traces of the division 

 which occurs in ('. gigot. The Spigelian lobe appears to me also to be a little 

 different in form. The annexed sketches will illustrate the form of the liver in the 

 two species C. torquata and €. personata. 



Professor Weldon discovered an interesting fact in the structure of the larynx 

 of Callithrix gigot, which he described as follows : — " 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 tlie possible existence of a howling apparatus in the male." The 

 larynx showing the ossification is duly figured by Mr. Weldon. I naturally looked 

 carefully at the larynx of the female Callithrix torquata to ascertain if there was 

 anything of the same kind to be seen ; but with entirely negative results. I can 

 find no traces of ossification in the thyroid cartilage in this sjiecies. 



The subdivisions of the lungs in Callithrix ajipear to ailbrd specific characters. 

 In C. gigot Weldon found the left lobe to be simple, and the right lobe to be 

 divided into three ; there was also a lobus impar. In C. torquata the left half of 

 the lungs was plainly composed of two divisions, and the right of three : the lobus 

 impar did not lie in the mediastinal cavity, which is widely open below the posterior 

 vena cava. Callithrix personata appears from the notes of Forbes to agree with 

 C. torquata in these points. 



The brain of the present species is illustrated in Plate XL, figs. 3 — 5. It 

 is naturally not very different from the three species, Callithrix moloch,* C. 

 nigrij'ron.'i,] and ('. gigot, whose brains have been illustrated ; but, nevertheless, 

 there are some few slight points in which the several species diverge. The 

 dimensions are practically those of the brain figured by Weldon.:} The extreme 



• Gratiolet, Memuirrs mir Irs Pli.i CMhraux, etc. This tignrc is copied by .'iir William Flower in his 

 memoir upon the brain of Stmiups (Trims. Zml. Soc. V., I'l. XXVIF., fig. II). 



t Kiikenthal .<c Ziehen, Jen. Zritnchr. xxix. p. 18. 



I hoc. eit., fig.s. .') and 6, p. 9. CaUithii.r (sp. inc.) has been also briefly described by liisohoff 

 {Ahhaitdl. K. Ila>j. Akail. X., 1870, p. 477). 



