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DR. J. ANDERSON ON MACACUS BRTJNNEUS. [Feb. 20, 



extremity of the pleurapophysial element of the next vertebra joins 

 the posterior angle of the ilium, and is closely applied to the pleura- 

 pophysial process of the second sacral. The fourth sacral has the 

 same form as the third, and has a lateral expansion, apparently 

 serially homologous with the process in front of it and with the 

 well-developed pleurapophysial element of the second iliac vertebra. 

 None of these vertebrae, however, have united; but they have all 

 the appearance as if tbey were to do so. The third sacral vertebra 

 has a low ridge-like spine ; but the fourth has its spinous process 

 reduced to a mere rudiment. The pedicles of the anterior zygapo- 

 physes of the second, third, and fourth sacral vertebrae are short, 

 and the facets are almost sessile on the arch. 



Sacrum and caudal vertebra 1 of Macacus brwmeus. 



The last caudal vertebra reaches only to the middle of the ischial 

 tuberosity ; but only nine out of the eleven appear externally in the 



