GENETIC TYPE AND THE ENDOCRIXES 485 



quently seen in parathyroids with otherwise usual structure. 

 The bitch furnishing this gland had a dachshund typed head 

 with a long muzzle, and was a fairly normal animal although 

 she possessed a disproportionately large thyroid gland. 



Figure 6, from 355 5 , is quite similar to figures 1 and 2, 

 from the two parent stocks. The double rows of cells form 

 typical cords, and the cytoplasm is more abundant and less 

 concentrated than in figure 5. The one peculiar feature of this 

 section is the high concentration of the bluish staining cells 

 in the peripheral region, which are shown by the darker 

 masses at the top of the section. This animal was also 3 

 years old when killed and had a partial Boston terrier typed 

 head with a prognathous undershot lower jaw. Sections 

 from the pituitary and the thyroid glands of this bitch are 

 illustrated in plate 89 (figs. 2 and 4). The pituitary is one 

 of the most cystic specimens in our collection and has very 

 little functional epithelium. The thyroid approaches in its 

 peculiar pattern that of the Boston terrier and has medium 

 and small sized irregular follicles as well as large numbers 

 of very minute ones. Parafollicular cells are scattered in the 

 interfollicular regions. These sections, in plates 89 and 91, 

 from three endocrine glands of the F 2 Boston terrier-dachs- 

 hund hybrid would indicate the highly pathologic state of 

 her endocrinic system. The bitch was certainly not a nor- 

 mally vigorous animal, nor for that matter were many mem- 

 bers of the F 2 generation of Boston terrier-dachshund hy- 

 brids. This may be seen by again referring to the mixed and 

 distorted types illustrated in plate 39, and particularly by 



353 $ (fig. 3), the extremely defective sister of the two bitches 



354 9 and 355 9 supplying the glands just discussed. 

 Sections from two other F 2 Boston terrier-dachshund para- 

 thyroids are shown in figures 1 and 3 in plate 92. Figure 1 

 is from 779 $ , a brother of 781 $ which supplied the cystic 

 section in plate 91 (fig. 4). This dog, 779 <?, was a definite 

 midget in type, being much smaller than any of his litter 

 mates, as shown in plate 30, figures 1-5 (p. 129). There are 

 no cystic formations associated with his parathyroid as there 



