No. 2.] THE HYPOPHYSIS OF AMIA. 505 
palazeostome and its connection with the stomodeum in other 
vertebrates to be a secondary condition correlated with the 
increased size of the forebrain and the loss of the adhesive 
organ. That such a condition as the connection of hypophysis 
and stomodzeum could come about through the secondary dis- 
placement of the hypophysis he considers “schwer zu ver- 
stehen.”” Whether the position of the hypophysis in these 
three forms is primary or secondary, depends, it seems to us, 
on whether the adhesive organ is a primitive organ formerly 
possessed by all vertebrates, or an organ which has made its 
appearance in only a few groups and has in these groups 
caused the displacement of the hypophysis from a position in 
the stomodzum to a more dorsal position. This question can 
scarcely be answered until we know more of the adhesive 
organ itself and its homologues. Until our knowledge on this 
subject is increased one of these alternatives seems to us nearly 
as probable as the other; although, as v. Kupffer points out, 
the early appearance and large size of the Acipenser hypophy- 
sis is probable evidence of its primitive character. 
Since the foregoing was written there has appeared a paper 
by Prather (1900) on the development of the hypophysis in 
Amia. The earliest embryo in which Prather has found the 
hypophysis is one a few hours before hatching, corresponding, 
therefore, very closely to Fig. 8 of the preceding article, In 
this stage he finds it in process of being differentiated out 
of the entoblast of the dorsal wall, of the foregut, ventral to 
the infundibulum, that is essentially in its adult position. 
His account thus differs from ours chiefly in two particulars: 
(1) He has not seen the early stages in the development of 
the hyphophysis as described by us. (2) He derives the 
hypophysis from the entoblast; whereas, according to our 
account, it is ectoblastic. 
Through the kindness of Dr. Eycleshymer one of us has been 
able to examine the sections on which Prather’s studies were 
made. They show what Prather has described. Having had 
an experience of many years in the preservation of Amia 
material and in the preparation of sections from it, we be- 
