2l6 DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 



formed an obstacle to the deepening of the sulcus which is avoided 

 in this way. 



It will be noted that, while the processes of folding and constric- 

 tion are progressive in a caudocranial direction, and this obtains of 

 later stages as well, that of dislocation begins at an intennediate point. 

 It has not yet affected the pars lata, and the caudal extremity of the 

 inclusion retains its fundal position. This raises the question of a 

 possible caudal growth of the pars cyhndrica, which could be accom- 

 phshed either by the extension of the fold or by proliferation. The 

 first alternative may, I think, be rejected. The caudal segments of the 

 inclusion are uniformly well constricted and never show the presence 

 of a fissure, as in the stages of the inception of the fold. That occa- 

 sionally some proUferation occurs here is highly probable. In a 

 minority of cases the caudal section or two of the inclusion are free, 

 before the separation of the pars cylindrica has progressed to its caudal 

 end. These cases are not numerous and the length of the free tip is 

 always inconsiderable. In such forms as the pig and chevrotain, a 

 considerable caudal process of horizontal direction can be distinguished 

 from the pars cylindrica, and is apparently due to proliferation. It 

 would appear, therefore, that in the cat this tendency is only excep- 

 tionally manifested to a very sUght degree; its suppression possibly 

 is correlated to the brachycephalism of the Felidas. 



The orbital inclusion is now composed of a pars cylindrica and a 

 oars lata, and manifests a slight tendency to growth lateral to the 

 buccomasseteric nerve, the processus lateralis. In the 12 millimeter 

 embryos it completes its form by the acquisition of a tapering cranial 

 extremity, the processus craniaUs. Hitherto its cranial end has been 

 blunt in the form of a broad flange which was suddenly effaced by the 

 opening of a fissure throughout its breadth. From this period the 

 cranial end shows a number of sections of diminishing width, the 

 fissure indenting their bases more and more as they are followed 

 craniad, until finally the inclusion is lost in the thick epithelium of the 

 buccal sulcus. As the pars lata does not diminish in sagittal length 

 during this process, the pointed extremity must be regarded as an 

 addition to the inclusion, which becomes an harpoon-shaped object, 

 with dorsoventrally flattened blade and rounded shaft, while the barb 

 is represented by the lateral process. It is still attached to the buccal 



