THE PINEAL BODY OF THE SHEEP 255 



color is as during the earlier weeks, white. The lumina are spanned 

 by delicate strands of a coagulum (fig. 7). The alveoli are more 

 numerous peripherally (fig. 6). They are circular in trans- 

 verse section, vary considerable in calibre, but have in no case been 

 seen to branch. As regards trabeculae, septa, follicles and cell- 

 types, the body at this stage is in all respects like the former. 



THE PINEAL BODY AT TERM 



The specimens in hand lack about a week of full term. How- 

 ever, the pineal bodies are in all respects, except size and number 

 of granules, like those of lambs (ca. 8 months). They contain 

 numerous alveoli of varying caliber and length, and considerable 

 of the cells contain small amounts of melanic granules. The 

 characteristic new feature here is the great abundance of follicular 

 arrangements of cells about central vascular connective tissue 

 trabeculae. Since all of the features of the adult pineal gland are 

 here present and in less complicated form, it seems desirable to 

 describe them more in detail. 



The body simulates a lobulated gland. The lobules are de- 

 limited more or less distinctly by coarser and finer reticular septa 

 of vascular connective tissue continuous throughout, and periph- 

 erally, through the coarser trabeculae, with the pia mater. The 

 lobules consist of one or several follicular aggregations of cells. 

 These are spherical or oval masses, the parenchyma of which 

 consist of two distinct types of cells with several intermediate 

 types. The framework of the parenchyma is a reticular structure 

 of delicate neuroglia fibers for the most part continuous with the 

 irregularly polygonal and flattened stellate neuroglia cells. Many 

 of the coarser fibers seem entirely free from the cells, as in typical 

 neuroglia tissue (Huber, '01, '03). The second main type of 

 cell, oval and spheroidal or polyhedral, occupies the interstices of 

 the neuroglia meshwork (fig. 8). Many of the cells still contain 

 numerous melanic granules, more especially peripherally and in 

 the walls of the alveoli or cysts. The latter are still abundant 

 and quite large. 



A conspicuous feature is the great vascularity of the pineal 

 body. Frequently capillaries terminate in the form of tangled 



