MAMMALIAN ALVEOLINGUAL SALIVARY AREA 335 



is ephemeral, beginning to be effaced at 22 millimeters. The caudal 

 portion of the sulcus is reduced next, and finally the whole from be- 

 hind forward. In the pig the sulcus has the same general history, 

 but is in embryos of 14-19 milhmeters a rather shallow concavity; 

 in the cat it is retarded and rudimentary. 



3. Sulcus intermedius (Schulte). In the figures of His and Chievitz 

 this appears as a shallow indentation of the alveolingual gutter, between 

 the lingual and alveolar sulci. In a human embryo of 20 millimeters 

 it is an obhque furrow extending from the region of the subma.xillary 

 ganghon about halfway to the frenulum. Its caudal extremity ap- 

 proaches the alveolar sulcus, its cranial the lingual, without joining 

 either. A minute epithelial keel is attached to its fundus. In an 

 embryo of 22 milUmeters the furrow had disappeared, but the keel, 

 though reduced, was still present. Its significance is problematic. 



4- Sulcus circumflexus (Schulte). The development of this furrow 

 is complementary to that of the plica subungualis, which it bounds at 

 the side and in front, where it is confluent with the Ungual nerve. It 

 extends gradually caudad in man, becoming confluent with the alveolar 

 sulcus. In the cat, apparently, it is independent throughout its exist- 

 ence; its caudal extremity extends beyond the lingual nerve. It 

 gives rise to the early sprouts of the lesser sublingual series in man and 

 in the cat. 



His ('S3) was the first to appreciate the peculiarity of the mode of 

 formation of the ducts of the larger sahvary glands. He added to 

 Reichel's locahzation of the submaxillary aniage in the lingual sulcus 

 its precise situation in reference to the lingual nerve, finding it to be 

 just caudal to the point at which the nerve turns ventrad of the sulcus 

 to enter the tongue. Unfortunately he mistook the pale center of the 

 aniage for a lumen, and was thus led to infer that its advance took 

 place by a bridging over of the sulcus. His assignment of the sub- 

 lingual gland to the alveolar sulcus is plainly stated to be conjectural, 

 nor is it possible from the context to tell whether the supposition has 

 reference to the Bartholinian or to the Rivinian elements. 



Two years later Chievitz published his admirable and important 

 paper. The opening paragraph is interesting in its expression 

 of the attitude of this first-rate investigator towards liis subject, 

 and the matter-of-course way in which a sound, but often over- 



