DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 279 



tached to the lingual sulcus; while between is an intermediate ele- 

 ment, which from its position appears to correspond to the dorsal 

 accessory submaxillary of the human embryo. The dorsal element is 

 the postglandular flange, which after the separation of the duct for a 

 time persists along the lingual sulcus, but eventually is reduced and 

 disappears. As yet these elements are rather vaguely defined, es- 

 pecially the junction of the postglandular flange with the intermediate 

 element, which is as yet more of a change of direction or a kink in the 

 anlage than an actual constriction. 



In a second embryo of 1,5.5 miUimeters the submaxillary has under- 

 gone important changes and the anlage of the greater subhngual has 

 appeared. A series of third sections is given in Figs. 129-138. It 

 is seen that the anlage has lengthened enormously and in a direction 

 craniad of the lingual nerve ; the advance of the duct has, therefore, 

 begun. In the degree of this process, not in its nature, the embryos 

 between 13.5 and 19 millimeters show a wide range of variation. In 

 the individual under consideration the gain is rather large, and in this 

 respect it is distinctly in advance of its stage. Turning now to the 

 structure of the anlage, in the region of the lingual crossing (Fig. 135), 

 it is seen to be a flange directed ventrad and slightly laterad in close 

 proximity to the nerve, and possibly in consequence of the presence of 

 the nerve, presenting a slight kink in its middle as though pressed upon. 

 The postglandular flange and intermediate elements are not very 

 clearly defined. Craniad (Figs. 131-134) the flange diminishes in 

 width, loses its kink, but retains its lateral deflection from the fundus of 

 the sulcus. The fissure indents its base increasingly and becoming 

 wider an open Ungual sulcus is formed (Fig. 130), to the fundus of 

 which the anlage is attached. Finally, the attachment becomes parie- 

 tal and its foldlike character is lost ; in Fig. 1 29 it appears as a solid 

 projection of epithelium of the lateral wall of the sulcus near, but not 

 at, its fundus. This character is retained by the cranial tip of the 

 anlage until the duct comes to rest, a constantly increasing interval 

 separating it from the fundus of the sulcus in later stages. 



Caudad the separation of the duct has begun. This is accomplished 

 by a solution of continuity in the flange in such a way that a portion, 

 the postglandular flange, is always left attached to the Ungual sulcus 

 (Figs. 136, 137, 31). This retains a fissure at its base, but rapidly 



