THE DEVELOPMENT OF THE SALIVARY GLANDS IN MAN 33 



changes its position in a manner so analogous, to the fold here in 

 question, that it can hardly be doubted that this is its homologue. In 

 the cat the orbital fold lirst appears in the plane of the mandibular 

 nerves, and from this point spreads craniad nearly to the angulus 

 oris, later to be displaced caudad as the sulcus lengthens. From the 

 new postangular segment of the sulcus the parotid takes origin as a 

 short fold, to which is soon added a sprout. There is, as a rule, an 

 increasing but variable interval between the anlages, but exceptionally 

 the fold of the orbital inclusion involves the whole interval and becomes 

 continuous with that of the parotid. The continuity of the parotid 

 with an entomasseteric duct (orbital inclusion) in one of Chievitz's 

 human embryos is inferential evidence of an early confluence of their 

 folds of origin. It is therefore possible that Hammar's fold may 

 refer to this condition and represent continuous anlages of the parotid 

 in its cranial, and of the orbital inclusion, in its caudal segment. 



4. Paulet. Embryo of 14.7 milhmeters, V.B.; 13.8 millimeters, 

 N.B. The length of the anlage is 300 /x, its distance from the angulus 

 oris 650 M. 



Im Grunde der Wangenfurche lasst sich eine Crista beobachten, welche vorn 

 in der Nahe der Lippenkommissur endet, hinten in eine rundliche Sprosse tibergeht 

 die in der Tiefe des Wangenblindsacks gelegen ist: dies ist die Parotisanlage. 

 Wie be! den Submaxillardrusen, kann man auch hier zwei Abschnitte unterschei- 

 den : einen epithelialen Strang, die Anlage des Ausftihrungsganges und den rund- 

 lichen Sprossen, die Anlage der Druse selbst. Dicse Bildungen entstehen in der 

 am meisten zuruckgelegenen Partie der Vestibularfurche; die knospenformige 

 Anlage des Parotiskorpers wendet sich zur ausseren Oberflache, von der sie .05 

 millimeters entfernt ist. 



As compared with the parotid of corresponding development in 

 the cat (13. 5-14 millimeters) this anlage is very long, but above all is 

 peculiar in its origin from the caudal portion of the buccal sulcus, 

 which in that form, as also in the pig, mole, tree-shrew, and chevrotain, 

 gives rise to the orbital inclusion, the parotid a rising from a more 

 cranial portion of the sulcus as in the following embryo of His. The 

 anlage of Paulet is not dissimilar to that of the orbital inclusion in the 

 cat of 13.5 millimeters, presenting the broad and narrow portions which 

 are characteristic of the structure in this stage. This raises a question 

 of the orientation of Paulet's reconstruction, for the broad portion of 

 the inclusion is cranial, the narrow, caudal. In his twelfth and thir- 



