68 P RATHER. [VOL. I. 



row encircling the lumen in a radiate manner, long spindle- 

 shaped in the upper and lateral parts, more rounded below. 

 The other cells appear to have a general tendency to arrange 

 themselves in rows pointing towards the center of the organ, 

 but this arrangement is modified by a secondary tendency to 

 be grouped about the secondary lumina and the longitudinal 

 channels. A marked feature of this and succeeding stages is 

 the indistinctness or total obscurity of the nuclei. 



A sagittal section at this stage shows the same peculiar 

 arrangement of cells about the lumina and channels in the 

 separate lobes. And the other characters of the hypophysis 

 are similar to those shown in the cross-section. The anterior 

 sphenoidal cartilage has now advanced to the posterior part of 

 the chiasma nearing the hypophysis, the posterior to a point 

 not far from the posterior point of the saccus, while dense skele- 

 togenous tissue continues to and below the saccus nearly to 

 the hypophysis. The perichondrium, as before, stretches across 

 from one cartilage to the other below the organ. The basilar 

 artery is now well formed, running along the base of the hind 

 brain up into the fold between the hind brain and the primary 

 forebrain. A blood vessel may be seen also just posterior to 

 the hypophysis beneath the point of origin of the saccus. The 

 saccus has enlarged, and in its cavity may be seen abundant 

 granular secretions. 



Passing from this stage to a stage between thirty and thirty-five 

 days, a sagittal section (Fig. 16) shows all parts much enlarged. 

 The finger-shaped saccus measures internally 31 1 /JL by 18 //. at 

 its narrow opening into the infundibulum, and 77 p at its widest 

 part. The granular secretions noticed in the previous stage 

 have increased in amount. While the sphenoidal cartilages 

 have enlarged and strengthened compared with the condition 

 in the previous stage, they have approached very little nearer 

 to the hypophysis ; but the connective tissue between the 

 hypophysis and the roof of the mouth has considerably 

 increased. The hypophysis at this stage has attained a size 

 of 3 59 /<< by 96^1. Increased lobing is not apparent from the 

 figure, but the scries shows a great increase in the number of 

 lobes and of the lumina in them. The arrangement and char- 



