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Cliarles Searing Mead. 



buried in cartilage; it still lies, however, nearest the upper surface 

 of the investing mass." And in his figure to which he refers (PL 

 XXXVIII, Fig. 2) he indicates the notochord as following a nearly 

 straight course which lies a little above the middle of the basal plate. 

 Kolliker (1879, page 444, ff.) in his studies on a pig embryo 32 mm. 

 long, noted accurately the course of the notiochord through the 

 cartilage, and also its enlargements, which he called the occipital and 

 sphenoidal swellings. 



Fig. 2. Sagittal section showing the course of the notochord through the 

 base of the skull and its two connections with the pharjmx. Line AB would 

 represent the section from which Fig. 5 was talcen. 



In the specimen, from which my reconstruction was made, the 

 notochord follows much the same course as it did in the Sus indi- 

 viduals which Kolliker studied. But, whereas in his the notochord 

 was continuous throughout, in mine its course is broken near the 

 middle of its passage through the basal plate, and each part leaves 

 this and gains a connection with the dorsal wall of the pharynx 

 (Fig. 2). The occipital and sphenoidal swellings are present, but 

 are not as prominent as Kolliker figured them. Anteriorly the 

 notochord leaves the basal cartilage and ends in the perichondrium 

 lining the floor of the hypophysial fossa. 



