230 DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 



angle is a spherical enlargement, the parotid sprout. This tapers 

 along the margin of the flange, but ceases to be distinguishable from 

 the intermediate portion craniad, and so does not reach the fundus 

 of the buccal sulcus. This marginal extension of the proliferation 

 foreshadows the parotid duct. A distinction is now possible between 

 the area of the flange destined to reduction, the intermediate portion, 



and the proliferation which forms the 

 definitive gland. In this also a distinction 

 may be drawn between the marginal tliicken- 

 ing which forms the pro-ximal segment of 

 the duct, and the bud at the angle which 

 will give rise to the distal duct system and 

 the secretory epithelium of the gland. 

 Fig. 95. Reconstruction of A parotid intermediate in size between 

 the right parotid aniage ^Yint of embryo No. 127 and those of the 

 of a 14 millimeter embrvo. .,,. ^ ' , . , 



„ , , • r. 11 • x't is millimeter embrvos is shown in a series 

 Columbia Collection, >jo. 



97. Dorsal view, X 200, ^^ alternate sections in Figs. 58-65. In its 

 reduced to 5. cranial sections it closely resembles the 



aniage in embryo No. 189 (compare Figs. 

 58, 59 with Figs. 49, 50). Caudad its flange is more compressed 

 (Figs. 60, 53) and its last sections distinctly broader (Figs. 61, 54). 

 The lateral border is shghtly thickened (Figs. 60, 61), but the thicken- 

 ing does not extend to the cranial end of the flange. The sagittal 

 length of the attachment, as reckoned by section counts, has slightly 

 increased, 107 fj. in this embryo as against 80 n in embryo No. 189. 

 This fact, taken in connection with the greater development of its 

 caudal segment and the retention of primitive conditions craniad, 

 supports the inference that the fold of origin is still advancing toward 

 the angulus oris. 



The bud springs from the lateral angle of the flange (Figs. 61, 

 62) ; it is directed ventrad, shghtly laterad and caudad, and is received 

 in a concavity of the dorsum of the facial vein (Figs. 61-63), the 

 tributaries of which encircle it. The lateral elements of the plexus 

 at this time are the larger and communicate dorsad with the ophthal- 

 mic vein (Figs. 63, 64). The sprout enlarges distad to a bulky 

 fundus; the sections are circular and deeply staining throughout. 

 Caudad of the parotid, the buccal sulcus runs out into a small ventrally 



