506 CHARLES R. STOCKARD AND E. M. VICARI 



The pituitaries from first generation hybrids derived from 

 crossing the bassethound and bulldog show the general topo- 

 graphic morphology of the bassethound gland, while the 

 histologic pattern and cellular relations in the pars distalis 

 are nearer those for the bulldog gland. 



Figures 3 and 4 (pi. 95) illustrate longitudinal sections of 

 F, hybrid pituitaries from animals 739 <$ and 742 £ . The 

 rather normal and quite active thyroid gland from 739 c? has 

 already been shown (fig. 3, pi. 93). Both figures 3 and 4 

 (pi. 94) would be considered fairly normal in their general 

 morphology. Yet in 742 6 the pars intermedia is very un- 

 usual in its relation to the pars nervosa. The pars inter- 

 media fails to intimately encapsulate and penetrate into the 

 tissues of the nervosa. The looseness of fit is probably due 

 to the over extensive area of intermedia during early stages 

 of development. This might be considered a bulldog-like 

 character, although the condition in 742 $ , with its relatively 

 smaller nervosa, is even more extreme than in the bulldog 

 itself (cf. tigs. 2 and 3). Diverticula from the residual lumen 

 pass into the pars tuberalis, and the outline of the lumen 

 itself is somewhat modified by foldings of the pars inter- 

 media. The relative proportion of pars nervosa to pars 

 distalis in the ¥ x is similar to that in the hound and is not 

 the distorted relation found in the bulldog. It should be re- 

 called that the Y x hybrids produce full sized litters and are 

 successful mothers with well adjusted maternal reactions, 

 in these respects resembling the bassethound and differing 

 from the bulldog. The pars distalis contains more connective 

 tissue than usual, and the cords and nests of epithelial cells 

 are distinct and loosely packed, although this pattern is not 

 so extreme as in the bulldog. Among the F, hybrids of adult 

 age the general proportion of acidophils to basophiles is very 

 variable, and ranges from 15 to 1 in females to more than 80 

 to 1 in males. The over abundant acidophile cells are fre- 

 quently of unusually small size and in some cases the chromo- 

 phobes arc quite large and resemble basophiles. 



