SG 



THE IS^ATUBAL HTSTORT REVIEW. 



pendent nucleus ; therefore, altliough it cannot be stated witli cer- 

 tainty, none will doubt the probability of the interpretation that in it 

 we see the sternal rudiment of a coracoid ; and this view received 

 further support from the fact that a similar structure is met with in 

 Crocidura. In this animal I find that the very broad anterior extremity 

 of the sternum presents a little projection or spine in the middle 

 line, behind which the two episternals are attached. To the whole 

 extent of the anterior border of the manubrium sterni external to 

 this spine is attached a cartilaginous lozenge-shaped plate, the ante- 

 rior and external angle of which is rounded off. 



Tig. 11. 



Episternal apparatus of Crocvlnra.—sf, sternum — e, 

 ep, episternum — cl, clavicle. 



[ St rib — CO, coracoid— 



The two cartilaginous plates project somewhat in front of the 

 point of attachment of the episternal bones. Their transverse dia- 

 meter is about twice as great as their antero-posterior. Their con- 

 nection with the manubrium sterni is not so intimate as in the case 

 of the cartilaginous pieces described above as existing in the Mouse ; 

 but there appears to be a limiting membrane between the two, com- 

 posed of connective tissue, so that the cartilages may justly be con- 

 sidered as independent structures. Their ossification, which only 

 consists in a partial calcification of the cartilage, is likewise indepen- 

 dent of the sternum, and appears chiefly in the superficial layers both 

 of the anterior and posterior surfaces, and in two or three different 

 spots simultaneously. In Sorea; also these plates are present, but 

 much less distinctly defined (Fig. 5), so that for confirmation of my 

 opinions regarding these structures I prefer to rest on Crocidura. 

 Now since, as has been already explained, we cannot refer these 

 structures to the sternum itself, since, moreover, they cannot be 

 considered as episternal pieces, these parts being already present 

 in connection with the anterior extremities of the clavicles, and lastly 



