DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 219 



orbitoparotid bridge. The usual condition is shown in Fig. 45 from 

 embryo No. 216. Here the cranial process is continued by a short 

 flange, fundal in position, but deflected ventrad, between which and the 

 parotid is a well-marked interval. The cranial process shows a slight 

 constriction at its union with the flange. With reference to adjacent 

 structures, the site of this junction is entomasseteric and opposite the 

 point where the deep facial vein crosses the sulcus on its way to the 

 orbit. This point maybe taken as the usual cranial Hmit of the process, 

 the length of which is subject to wide variations. The caudal half 

 of the pars cylindrica is attached in a ventral parietal position and 

 is well constricted throughout (Fig. 45). In embryo No. 2ig, how- 

 ever, its caudal extremity is still fundal and unconstricted. The late 

 persistence of these primitive conditions suggests again the possibihty 

 of a caudal extension of the inclusion at least as a variant, but hardly 

 warrants a positive conclusion. In the same embryo the lateral process 

 is remarkable for its bulk as well as for its length. The angle between 

 it and the pars cylindrica lodges the buccomasseteric nerve. 



The separation of the inclusion is completed first at its cranial ex- 

 tremity. It occurs by a subterminal constriction, as in Fig. 45, leaving 

 attached to the buccal sulcus a short ventrally directed remnant of the 

 flange, which soon disappears. The time of separation is subject to 

 some variation. The tip was free in one embryo of 15 millimeters. 

 The latest period at which it was found attached was 19.5 millimeters ; 

 in two embryos of this length it was attached on one side in each. In 

 fifteen embryos ranging in length from 16.5 to 19 milhmeters the tip 

 of the cranial process was found free seventeen times, attached thirteen 

 times. In some of these embryos the tip was close to the buccal sulcus, 

 which retained a rudimentary flange for a section or two craniad of it, 

 indicating that separation had just occurred. In the older embryos 

 in which attachment persists the cranial process is exceedingly long 

 and tenuous, extending craniad of the deep facial vein. In the 15 

 milUmeter embryo in which the inclusion was free, the cranial process 

 was short and blunt, not reaching the vein. It would seem, therefore, 

 that the length of the cranial process depends upon the time of separa- 

 tion, and this in turn is dependent upon the degree of flange formation 

 in the orbitoparotid interval. Inclusions of the type of embryo 219 

 (Fig. 44) separate late and have long tenuous cranial processes, those 



