An Analysis of the Jnxta-Neural Epithelial Portion etc. 273 



irregular, convoluted cords in a thick stratum surrounding the infun- 

 dibular process. 



b) Cells. The cells are of the faintly basophilic variety, with 

 abundant homogeneous cytoplasm and large vesicular nuclei. 



c) Vascularity. There are very few blood vessels in this region. 



3. Histological characters of the pars distalis (plate XVIII, flg. 39). 



a) Cellular arrangement. The cellular arrangement is that of 

 convoluted cell cords. 



b) Cells. The cells are of the deeply acidophilic type, with gra- 

 nular cytoplasm and small vesicular nuclei. 



c) Vascularity. This part is rich in vascularity. 



4. Adult Common Fowl. Specimen H55 (plate XII, figs. 15 and 16). 

 In the fowl the three neural portions of the hypophysis are 



present. The saccular eminence [9] is a relatively more extensive 

 structure than in the other species examined. From its ventral aspect 

 it has the appearance of a large, median protrusion from the floor 

 of the diencephalon. Its ventro-cephalic surface [9 a] bears a close 

 resemblance to the conditions observed in the rat, sheep and rabbit; 

 its caudal surface [9 b] is more extensive than is the case in any of 

 the other animals studied. From the center of the saccular eminence 

 [9] the infuudibulum [10] is given off and this in turn proceeds caudad 

 to terminate in the expanded infundibular process [11]. This structure 

 differs from the usual type alreadj^ described, not only because the 

 recessus infundibuli [8] is continued into the distinct recessus processi 

 infundibuli [16], but also because the latter recess is here very much 

 branched, a characteristic observed in many sauropsid forms. 



In the epithelial portion the three typical parts appear in their 

 usual arrangement. The pars tuberalis [12] covers the eminentia 

 saccularis [9] on its ventro-cephalic [9a] and caudal surfaces [90] and 

 forms a nearly complete investment of the eminence. The pars in- 

 fuudibularis [IS] is in contact with the ventral surface of the infun- 

 dibular process [11] but fails to surround it. The pars distalis [14], 

 here, perhaps better than in any other form, fllls the condition im- 

 plied by the term. Its removal from relation with the nervous system 

 is distinct; it is not even continuous with any portion of the pars 



Internationale Monatsschrift f. Anat. u. Fhys. XXX. 18 



