DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 30I 



wall of the sulcus. In the 5 1 millimeter embryo the anlages of the mesal 

 row are still fuiidal, the lateral are parietal, in position. In the 70 milU- 

 meter embryo both are parietal and at some distance from the fundus. 

 In the adult these glands open about midway between the fundus and 

 margin of the Hp. The sprouts never show any formation of keels 

 at their attachments, and a great part of this displacement occurs 

 after they have acquired a lumen. The process must therefore be 

 referred to the conditions of growth in the sulcus itself, which produce 

 a rolling of the epitheUum at the fundus as the sulcus deepens. Here 

 is a clear case of the assumption of a secondary parietal position by 

 simple glands, which bears out the argument for a hke process in the 

 more difficult cases of such keeled glands as the parotid and sub- 

 maxillary. 



In the 19 millimeter embryo (Fig. 144) the series extends approxi- 

 mately the whole length of the sulcus. This arrangement is main- 

 tained in subsequent stages (Figs. 106, 109, 114) and in the adult. 

 That this is accomplished by the addition of new members at the 

 cranial end of the series is rendered probable by the smaller size of 

 the sprouts in this position. 



The glands of the stomal ridge are present only in the 70 miUimeter 

 embryo. The ridge extends, diminishing in size, from the parotid 

 orifice to the orbital angle. Dorsad it is limited by the superior 

 alveobuccal sulcus; ventrad by the subparotid furrow, which is 

 actually no more than a slightly deepened angle, defining the ridge 

 from the vertical plane of the cheek. On the ridge in the line of its 

 greatest prominence open the ducts of the parotid and orbital glands, 

 and on the left side, also, of an orbitoparotid. The sprouts of the 

 ridge glands are attached to the surface of the ridge near the ventral 

 sulcus just mentioned (Fig. 116). They are all advanced beyond the 

 stage of the hemispherical anlage, and exist as short cylinders rounded 

 and very slightly enlarged at their extremities. On the left side 

 there were four, viz. one immediately ventrad of the first orbital, 

 two approximately below the second, near the caudal end of the furrow, 

 and a fourth in a corresponding position near the third orbital orifice 

 (Fig. 114). The first of these is the largest. Its duct runs caudad, 

 diverging slowly from the mouth to near the border of the masseter; 

 here it turns rather abruptly laterad, immediately ventrad of the bud 



