THE DEVELOPMENT OF THE SALIVARY GLANDS IN MAN 51 



in parls of the duct, which passes the lingual nerve and its ganglion, 

 turning ventrad and laterad beyond the mylohyoid muscle into a well- 

 defmed roundish area of richly nucleated connective tissue. The 

 duct here di\ides into two primary branches: one directed caudad 

 bears two rounded terminal buils; the other continues the direction 

 of the duct and has three similar enlargements. From the lateral 

 surface of the epithelial crest of the submaxillary arises a short roimded 

 process, the sublingual gland. 



13. Columbia Collection, No. 325, length 20 millimeters, V.B. 

 (Figs. 4-20). The alveolingual regions are deep gutters beside the 

 tongue, almost horizontal in course, converging craniad and becoming 

 confluent in front of the frenulum. The bounding sulci, the lingual 

 (S) mesad and the alveolar {14) laterad, are well defined. The latter 

 is almost sagittally directed, and near its cranial extremity crosses 

 Meckel's cartilage (21) dorsally (Fig. 6), ancl approaches the dental 

 ridge (29), which is interrupted near the point at which the furrow 

 terminates (Fig. 4). No glandular anlages are attached to the sulcus 

 in this embryo. The lingual sulcus (S) forms the boundary between the 

 tongue and the alveolingual gutter. It begins a short distance behind 

 the frenulum (Fig. 6), and diverging from its fellow caudad, is continued 

 into the lateral border of the pharynx, which it joins almost at right 

 angles (Figs. 5 and 19). Defined by these boundaries the alveolingual 

 region as a whole narrows caudad, so that at the level of the lingual 

 nerve it is not more than half as wide as at the frenulum (Fig. 4). The 

 increase in width craniad is in part due to the extension of the region 

 mesad at the expense of the tongue, which it undermines increasingly 

 as the frenulum is approached (Figs. 6, 7, 12-17). The lateral surface 

 of the tongue falls into two areas, separated by a blunt angle (ig) ; 

 the upper, nearly vertical, looks to the palate process, the lower, 

 narrow and uneven (iS), corresponds to the extension of the alveo- 

 Hngual region just mentioned. Following CHevitz, we may term this 

 the sublingua; the angle between it and the vertical surface of the 

 tongue, the plica fimbriata. Both begin a short distance beliind the 

 frenulum and diminish caudad (Figs. 7, 12-17). 



Three solid anlages are attached to the lingual sulcus; all have a 

 triangular shape and increase in size caudad, where they terminate in 

 free sprouts. The larger of these is sulcal in position and is continued 



