DEVELOPMENT OF THE HYPOPHYSIS 393 
‘Stage K.’ Soon after this its terminal part dilates and the 
hypophysis is completely constricted from the mouth. 
Reichert (’77) in a description of some cleared embryos of 
Acanthias remarked on the position of the hypophysis and its 
relation to the notochord. He opposed the theory of the ecto- 
dermal origin of the hypophysis in Acanthias. 
Rabl-Riickhard (’80) in his work on the relations of the noto- 
chord, confirmed Miiller’s observations concerning the hypophy- 
sis. He stated that there is a ventral secondary outpouch- 
ing from the hypophysis in a 60 mm. Acanthias. In an embryo 
corresponding to Stage K of Balfour he has perhaps mistaken 
the connection between the premandibular somites for the 
hypophysis. This seems probable from the position as well as 
from the fact that he found no connection between this structure 
and the mouth at this time. 
In 1888 Edinger published a paper on the comparative anatomy 
of the forebrain. He stated that in Torpedo the hypophysis 
is at first a simple outpouching of the mouth which later develops 
secondary outpouchings. 
Sedgwick (’92) in his work on Scyllium and Raia made the 
statement that the first rudiment of the mouth extends into the 
pituitary body. 
Von Kupffer (94) reviewed the literature on the development 
of the hypophysis and gave some results of his own work. He 
thought that the hypophysis is not derived entirely from ecto- 
derm, and his observations on other vertebrates supported his 
view that the hypophysis is partly of entodermal origin. 
Hoffmann (’96) described the early stages in Acanthias de- 
velopment. He stated that the hypophysis develops entirely 
from ectoderm. He found the first definite outpouching anterior 
to the buccopharyngeal membrane in 13 to 14 mm. embryos. 
He also described a yellowish pigment in the buccopharyngeal 
membrane which could still be seen in the stalk of 25 mm.embryos. | 
Ha'ler (96) gave an account of the development of the hy- 
pophysis in Mustelus. He described the position of the organ in 
a 22 mm. embryo and called attention to the low epithelium 
found at the opening of the hypophysis into the mouth. The 
