THE PELVIC LIMB 



(1906) has illustrated some of the steps in its evolution by the fossil 

 evidence (fig. 50) whereby it is indicated that the ilium has become more 

 slender but has not been shortened, the pubis has suffered suppression, 

 and the ischium slight elongation and alteration in shape. 



Figure 51. Pelvic bones of Cetacea: {a) the zeuglodont Basilosaurus ; (b) Sib- 

 baldus ; {c and d) Balaenoptera physalus; (e) Megaptera; (/) Physeter; 

 (g) Mesoplodon; and {b) Lagenorhynchus: {b, d, and e are redrawn from 

 Augustin, and c, g, f, and h from Abel). These are supposed to be in right 

 latero-ventral aspect. 



Abel's figure of this region in a manati from Surinam (fig. 50) indi- 

 cates that in this family there has been a fundamentally different proce- 

 dure. He claimed that a vestigeal femur is present, attached near the 

 anterior end of the pelvis ; hence that the ilium is greatly reduced. The 



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