192 DEVELOPMENT OF SALIVARY GLANDS IN THE DOMESTIC CAT 



cus and the cutting off of a tube of epithelium. Hamniar modified 

 this view, describing a blind fold or flange, which, losing its continuity 

 with the oral epithelium, becomes a soHd rod of cells, only secondarily 

 acquiring a lumen. In this Sudler concurs. Hammar described a 

 similar process for the parotid, but in this case he held the result of the 

 constriction to be hollow, as in His's view of the subma.xillary. Sudler 

 pointed out that here, also, the aniage was solid. In this Sudler and 

 Chievitz are undoubtedly correct. Yet Hammar's assumption that 

 the processes of formation of these ducts should be of the same nature 

 is more than plausible. It seemed, therefore, desirable to utilize the 

 series of cat embryos in the Columbia Collection for the reinvestiga- 

 tion of this point in particular. 



The material comprises the following embr^'os cut transversely in 

 serial sections : — 



8 mm. 89, 102. 

 8.5 mm. 285. 



9 mm. 106, 265, 268. 

 9.2 mm. 136. 



9.5 mm. 132, 133, 239, 269, 273. 



10 mm. 79, loi. III, 112, 113, 114, 140, 237, 272, 274. 

 10.3 mm. 81. 



10.5 mm. 118, 120. 



11 mm. 77, 98, 213. 

 II. 5 mm. 251, 256. 



12 mm. 78, 100, 217, 263. 

 12.5 mm. 264. 



13 mm. 92, 107, 262. 

 13.5 mm. 76, 189, 223. 



14 mm. 97, 122, 127, 142, 210, 211, 212, 214. 



15 mm. 75, 91, 160, 216, 218, 219, 243, 244, 245, 246. 

 15.5 mm. 141, 143, 215, 247. 



16 mm. 95, 96, 222, 224, 230, 248, 260. 

 16.5 mm. 240. 



17 mm. 198, 258, 259. 



18 mm. 87, 88, 275, 278. 



18.5 mm. 199, 250, 254, Princeton Collection, No. 21. 



