THE TRUE CiECAL APEX, OR THE VERMIFORM APPENDIX. 95 



Anthropoidea. 



In the Anthropoids, a vermiform appendix definitely makes 

 its appearance. It is present as a distinctly differentiated 

 portion of the alimentary canal in the Gibbon, the Orang, the 

 Chimpanzee, the Gorilla, and in Man,. — that is, in the Simiidie 

 and Hominidse. In the lower Anthropoids a distinct vermiform 

 appendix is not present ; consequently, in the following animals 

 the caecal apex was, as usual, examined : — 



Hwpale jacchus, the common marmoset. 

 Midas Tufimanus, the red-handed tamarin. 

 Cynopithecus niger, the black ape. 

 Cercopitheciis albigularis, Sykes' monkey. 

 Cercopithecus mona, the Mona monkey. 



As the first five of these specimens all closely resemble each 

 other, they may be briefly referred to together. In all of them 

 the lymphoid tissue is present, but it is diffused throughout the 

 length of the caecum. It tends to be best marked at the csecal 

 apex ; and in the last of the series, the Mona monkey, there is 

 evidence of a special tendency to germ centre formation. In 

 the red-handed tamarin there is a well marked collection of 

 lymphoid tissue at the csecal apex. 



H0MINID/E,--Mitn. 



The microscopical appearances of the human appendix are too 

 ell known to require description. Suffice it to say, that the 

 results of the numerous examinations of human appendices 

 made in connection with this research confirm in every detail 

 the conclusions arrived at by such well known writers as Clado 

 (2), Kelynack (3), and Fowler (4). The appendix of Man is 

 characterised by its large amount of lymphoid tissue, sometimes 

 diffuse, but more frequently, especially in the young, aggregated 

 together into germ centres. In fact, from its microscopic 

 appearances, it well deserves the name which has been applied 

 to it of ' aVjdoniinal tonsil.' 



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