226 Henry Fox 



trally they unite into a common vessel which opens into the inferior 

 jugular vein. 



In the 12 mm. and 13 mm. pigs the carotid gland forms a mare 

 regularly circumscribed, voluminous mass (Figs. 9-10, C.GL). It re- 

 tains the same topographic relation to the third pouch as before, but 

 has increased considerably in size (Fig. 13). Its follicular structure 

 is clearly shown, and reminds one of that of the liver. Like the latter, 

 it consists of a reticulum of numerous, closely intertwined follicles inter- 

 penetrated by a rich system of capillaries, the latter derived from the 

 carotid artery (Fig. 53). 



The gland and the associated solid wall of the pouch (= dorsal plate 

 of the th5'mus) are intimately connected with each other (Figs. 38-40). 

 In many specimens, owing to unsuitable staining, the two parts cannot 

 be clearly distinguished from each other. In those appropriately double 

 stained with haematoxylin and Bordeaux red or with alum-cochineal 

 and orange G the definitive reticular structure of the gland is clearly 

 shown. 



In the 14 mm. pig (Figs. 14-15) the carotid gland shows no specially 

 noteworthy features. On the dorsal side it projects considerably above 

 the upper edge of the thymus and there comes in contact with the 

 inner part of the fimdus praecervicalis (F.Pc). 



In the 17 mm. pig (Figs. 19-20) the carotid gland appears to difffer 

 only in size from that just described. The same remark applies also to 

 an 18 mm. animal (Figs. 45-46). 



In the 20 mm. pig (Figs. 23-24) the carotid gland forms a mod- 

 erately large ovoid organ lying to the outside of the sinus piriformis 

 (S.Pi.). It is distinctly follicular in structure, but its individual 

 follicles show no lumen. 



In cats of 10.7 and 15 mm. the carotid gland is similar in essential 

 respects to that in the pig last described. It appears to be less com- 

 pact than the latter, the interspaces between the follicles being rela- 

 tively larger (Fig. 63, CGI.). 



In the pig of 24 mm. (Figs. 29-31) the carotid gland (C'.Gl.) shows 

 no peculiar characteristics. 



In the cat of 23 mm. (Fig. 66) the carotid gland shows no special 

 features. It resembles essentially that in a 15 mm. example. 



In the pig of 32 mm. (Figs. 34-35, C.Gl.) the carotid gland has the 

 same characteristics as hitherto, but is closely invested by the lobules of 

 the proliferated fundus praecervicalis. 



