296 Natural History Bulletin. 



and entoderm is a question concerning which there may reason- 

 ably exist a wide difference of opinion. 



In this paper the nomenclature is that of Balfour, with but 

 few ex'ceptions. No new terms are introduced, but an attempt 

 is made to give a more exact meaning to certain words. This 

 seems necessar}'^ in order to enable these observations to be 

 used advantageously in attempts to trace homologies. These 

 four terms are pituitary body, hypophysis cerebri, infiindibidum 

 and processus infundibidi. Throughout the literature on this 

 subject, pituitary body is used synonymously with hypophysis^ 

 or hypophysis cerebri. The synonymous use of these terms 

 is not desirable or justifiable; for the hypophysis cerebri in 

 Mammalia does not develop into what is usually known and 

 described by anatomists as the pituitary body. The pituitary 

 body is the product of both hypoph^^sis cerebri and processus 

 infundibuli. 



Equally erroneous is the statement that the infundibulum 

 enters into the formation of the pituitary body. The infun- 

 dibulum in the embryo kitten passes down on the ventral side 

 of the hypophysis cerebri, while the process given off from 

 the infundibulum higher up passes to the dorsal side, as may 

 be seen in figure 6. It is this latter structure, the processus 

 infundibuli, which, uniting with the hypophysis cerebri assists 

 in the formation of what is known in the adult as the pituitary 

 body. 



The term pituitary body should be reserved for the struct- 

 ure which in higher Vertebrates results from the the union of 

 the hypophysis cerebri and the processus infundibuli. 



The word itself, and its application to the structure under 

 consideration, is of some historic interest. It is from the 

 Latin pitiiita, given thus in the Century Dictionary: [L., 

 mucus, phlegm; prob. with loss of initial S, < spuere pp. 

 spidus, spit out.] The old idea of the function of this pitui- 

 tary body is still expressed when it is called the pituitary 

 gland, and probably the idea will be perpetuated in the use of 

 this word, just as old notions are preserved to us by such 

 words as artery and courage. 



