180 



Herrini; 



cat embiyos, but have not met witli another specimen showin^^ actual con- 

 tinuity of both cavities, altlioucjh it is not unusual to find the appearances 

 shown in figs. 10 and 11, where a somewhat similar condition exists; a 

 canal runs backwards from the central cavity of the posterior lobe to meet 

 the epithelium formed from the buccal invao;ination. In some kittens 



he c <1 f 



%. 



n, 



J 



•'V,V 









Fig. 10.— Mesial sagittal section through postero-supeiior angle of the 

 posterior lobe of the pituitary of another kitten near full time, 

 drawing from a photograph. 



h, central cavity of posterior lobe ; c, substance of posterior lobe ; d, canal from 

 cavity of posterior lobe running backwards into e, epithelial cells of tlie pars 

 intermedia; /, cells of pars intermedia investing posterior lobe below. 



there is an indication of a tu])ular character of tlie epithelium of the pars 

 intermedia in this situation, and the central cavit}" of the posterior lobe 

 appears to run into it. In older animals epithelial cells often invade the 

 tissue of the posterior lobe in the position in which the canal is indicated 

 in the figures, and may come to lie in the central cavity. In one adult 



