264 DEVELOPMENT OF SALFV^ARY GLANDS IN THE DOMESTIC CAT 



in later stages of development, which the frequency of orbitoparotids 

 in the adult would indicate (Part V, page 164). 



Turning now to the occurrence of the several varieties of orbito- 

 parotids in the three groups, the first is seen to be wholly composed of 

 those of angular position. That this is not the only site of the manu- 

 facture of orbitoparotids appears from a comparison with group 

 II. For granted that the embryos of this group were equipped with 

 twenty-four orbitoparotids at their entrance upon this period, and 

 that the seven angular sprouts are all of new formation, an unnecessary 

 concession, there are still two sprouts in excess, which cannot be 

 accounted for by displacement of the original sprouts of group I 

 along the parotid or along the buccal sulcus, and which, therefore, must 

 have originated in one or other of these positions. The statistics 

 of the third group strengthen this \'iew. Angular sprouts are no longer 

 formed, the intermediate portion of the flange having disappeared. 

 And yet there is an excess of eleven elements to be accoimted for. 

 Further in this group a large number have been reduced to inclusions. 

 In the adult no inclusion has yet been found, and again the proportion 

 of orbitoparotids has increased. 



It would appear, therefore, that orbitoparotid elements are formed 

 during the late stages of development, as well as the early, and at an 

 increasing rate. Their site is certainly the oral epithehum. The pos- 

 sibility of their formation from the parotid duct must also be granted, 

 for some of the inclusions of group III have a parotid course, and yet 

 the elements of this position have not decreased proportionately. If 

 the recurrent branches of the duct shall ultimately prove to be orbito- 

 parotids, a high degree of productivity must be conceded to this source. 

 Of whatever nature they shall prove to be, a formation of these branches 

 also in late periods of development must be taken into consideration, 

 on account of their frequency in the adult. 



THE ORBITAL GLANDS 



The topography of the early anlages of these elements differs but 

 slightly from that of the glands of the adult. It will facihtate the 

 account of their development briefly to recapitulate the conditions in 

 the adult, for the details of which the reader is referred to Part V. The 



