496 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



of the lobe. The spider-cells, however, which only differ from 

 those found in the cerebral tissues by their larger size in pro- 

 portion to the length of their tentacles, outnumber the other 

 cells as the upper infundibular region of the lobe is reached. 



The cells included in the second class are all, as stated, 

 distinguished by one or more protoplasmic extensions, which 

 insinuate themselves between all the elements intervening be- 

 tween their starting-point and the infundibular area referred 

 to, where they break up into figures. The lowermost of 

 these, the ganglion-cells shown in Fig. F, Plate I, and Fig. /, 

 Plate II, exemplify this type very well, since their extensions 

 traverse the entire organ in an upward direction and end in 

 the upper infundibular area. Higher up in the organ large 

 pyramidal and oval cells are found (Fig. G, Plate I; Fig. g, 

 Plate II; and g, Plate III), the terminal subdivisions of which 

 break up into exceedingly fine feathery filaments. The only 

 axis-cylinder of this cell, after distributing a few branches to 

 neighboring elements, continues upward and subdivides, when 

 near the upper margin of the infundibular region, into a com- 

 plex net-work which entwines the alveoli found there. A third 

 type, characterized by short dendrites and many hair-like 

 processes (Fig. jET, Plate I, and Fig. h, Plate III), is found 

 throughout the entire nervous area and also gives off one long 

 dendrite, which extends a long distance upward and forward; 

 this extension may possibly reach the infundibular region or 

 its neighborhood. Coming from every direction, these long 

 dendrites seem, at any rate, to point all toward this one region. 

 The other dendrites are short and distinguished by the pres- 

 ence of more or less numerous hairy processes, while some of 

 the terminal ramifications are ball-tipped suggesting a pos- 

 sible identity as collectors of energy, which, transformed in the 

 body of the cell, is directed upward by the long dendrites. 



In the infundibular region of the lobe i.e., the cellular 

 elements of the third class the final ramifications of the long 

 dendrites form an extremely complex aggregation of tufted 

 figures, wavy threads, and feathery protoplasmic ramifications. 

 In the midst of this maze of nervous elements certain cells are 

 to be found, the like of which Berkley has not been able to 

 detect in any part of the central or peripheral nervous system. 



