372 



actual end. He says: "In the specimen from which my reconstruction 

 was made, the notochord follows much the same course as it did in the 

 Sus individuals which Koelliker studied. But whereas in his the 

 notochord was continuous, 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." 



Mrs. Gage^) has found that in a certain percentage of pig embryos, 

 the notochord reaches the retropharyngeal region and at that point is 

 in contact with the roof of the pharynx. 



Koelliker2) too has studied the course of the notochord in pig 

 embryos and found it continuous though following a curve very like 

 that shown b}' Mead. 



Meyer^) believes the pharyngeal bursa to be identical with 

 Seessel's pocket. He summarises his results as follows: 



Fig. 1. (a) Diagram of end of notochord pharyngeal recess and hypophysis. 

 (b) (c) Diagram of end of main body of notochord. 



„Aus meinen Befunden aus jüngeren menschlichen Embryonen 

 geht hervor, daß die Bursa pharj-ngea unabhängig von der Eathke- 

 schen Tasche im 2 Monat bei ca. 14 — 28 mm Scheitelsteißlänge un- 

 gefähr unter 5 Fällen einmal zur Ausbildung kommt und stets mit der 

 Chorda im Zusammenhange steht." 



,,Der umstand, daß die Bursa pharyngea der Erwachsenen eben- 

 falls an der Schädelbasis fest adhärent gefunden wird, weil sie die 

 Eibrocartilago basilaris durchbohrt, erlaubt den Schluß, daß die 

 Bursa pharyngea media der Erwachsenen mit der bei Embryonen 

 beschriebenen, also der SEESSEL'schen Tasche identisch ist." 



Huber^) has reached the conclusion that the pharyngeal bursa 



1) Gage, "Science"'. New Series, Vol. 24. 



2) Koelliker, Entwickelungsgeschichte des Menschen und der höheren 

 Tiere. Leipzig 1879. 



3) Meyer, Anat. Anz., Bd. 37, 1910. 



4) Huber, Anat. Record, Vol. 6, Xo. 10, 1912. 



