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THE NATURAL HISTORY REVIEW 



or four m.m. (itli of an inch) iu length by a true joint (see 

 ^ig. 6). 



Fig. 6. 



Episternal apparatus of Cricetus : — ep, episternum ; el, clavicle ; c, first rib ; st, 

 sternum. 



This piece of cartilage terminates in a pointed extremity which is 

 attached to a slight indentation on the posterior surface of the 

 manubrium sterni, so that when looked at from before, only a very 

 small portion of the episternals can be seen. I have been unable to 

 find in this animal any joint at the back of the sternum, or any 

 ossification or calcification of the cartilage,which I do not however con- 

 sider to be a matter of much importance since its presence or absence 

 is probably connected with the age of the animal. I have not been 

 able to discern any striking peculiarities besides those I have already 

 described, in the remaining Eodentia provided with fully-developed or 

 rudimentary clavicles, and it seems more than probable, that in all of 

 them one or other form of episternal apparatus is present. In the 

 Hedgehog (Fig. 7, ep.) I find episternals similar in form to those of the 

 Hamster ; but inasmuch as they are attached to the anterior border 

 of the sternum, they are easily visible from before. 



Fig. 7. 



Episternal apparatus of Erinaceus EnropfBvs (Hedgehog), as seen on vertical 

 section :—<?;?, episternum ; c, clavicle ; c', first rib ; c^, second rib ; st, sternum. 



