72 FREDERICK TILNKV AM) Ll'THKR K. WAKKKX 



8. Tin ilcn-lojHin nl f tin r /ii/>/i ijKcal complex in nnunmals 



The only portion of the epiphyseal complex \vliich appears in 

 the anln^c in mammals is, in all probability, the proximal part 

 of the pineal organ, for there is no evidence of the anterior or 

 parapineal clement. Mihalkovicz- 7 ' in 1877 .nave a description 

 of the development of the organ in mammals and called attention 

 to the fact that it resembled very closely that of birds. At first 

 the anlage is a simple evaluation, then several lateral diverticula 

 about the same size make their appearance and later give rise to 

 many follicles. The lumen of each follicle from the beginning is 

 smaller than that in birds and ultimately is obliterated so that 

 there are finally solid follicles surrounded by connective tissue 

 and blood vessels. The epiphysis always retains its connection 

 with the interbrain by means of a set of peduncles. These 

 peduncles vary in their arrangement and number according to 

 the form of the animal. In man they are described by Test ut 393 

 as being three pairs, known respectively as the superior, middle, 

 and inferior peduncles of the pineal body. Alihalkovicz gave 

 his description of the relations of the anlage to the roof-plate as 

 Jie observed them particularly in the rabbit. 



Kraushaar- 21 in 1885 confirmed these findings in the mouse 

 and Kolliker- 11 in 1879 in the rabbit and sheep. d'Krchia 109 in 

 ls|)0 found that the epiphysis in the guinea-pig is laid down as 

 a solid bud or sprout, while in man it has in its anlage a small 

 lumen from the beginning (fig. 39). 



Neumej'cr'-"^' in 1S99 found in the rabbit that the epiphyseal 

 anlage was a long, tubular structure with a narrow lumen and 

 considerably convoluted. The original lumen of the anlage is 

 ultimately reduced until it occupies the proximal portion only 

 where it is known as the ivcessus pinealis, according to Heichert, 326 

 or the recessus infrapiiiealis, according to Mihalkovicz. 275 This 

 distinction takes account of the description already given by 

 lleidierl of the sii| >ra pineal recess. 



In >tudying the development of the diencephalon in the 

 domestic cat one of the authors illustrates by reconstruction 

 models of the following embryos: In rcli* <l'>niexiicti, the pineal 



