252 DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 



Table n 



From the first table it is apparent that the orbital fold regularly 

 advances to the plane of the deep facial vein, and in a majority of 

 cases to its cranial half, while in the larger embryos in which the at- 

 tachment is retained it has a decided tendency to advance beyond the 

 vein. The maximum of advance is attained in the 19.5 millimeter 

 embryo (No. 277), where the attached tip of the inclusion is at the 

 level of the border of the raasseter, only 57 >i caudal to the parotid, 

 while the distance from the parotid to the deep facial vein is 267 fi. 



In the second table it is seen that a large majority of the free inclu- 

 sions also extend to the plane of the vein, but that as development 

 proceeds they tend to assume a postvenous position (embryo of 21 

 milUmeters). This is true of the late stages of the inclusion also. A 

 long and tapering cranial process is characteristic of the inclusions 

 which extend to the cranial half of the vein or farther, whether free or 

 attached, while in those of postvenous position the process is rudi- 

 mentar\-. It is possible that the position and shape of the process 

 may in some cases depend upon a premature separation, before the 

 fold has made any considerable advance. In the 15 millimeter 

 embryo (No. 216) the cranial process is short, but already constricted, 

 at its junction with its flange (Fig. 45) and evidently on the point of 

 separation. On the other hand, the inclusions may, and probably do 

 in many cases, shorten after separation, either by retraction, or by 

 reduction of the cranial process. If embryos of the same length are 

 compared in the two tables, the attached inclusions in general are 

 found to extend farther craniad than those that are free. In manv of 



