DEVELOPMENT OF THE HYPOPHYSIS 397 
in diameter and usually have asmalllumen. They are composed 
of cylindrical cells. The tongue-like anterior end, he stated, was 
of similar structure. He was of the opinion that the glandular 
portion arose from the mouth. 
Rohon (’79) described an hypophysis composed of tubules in 
selachians. It is a triangular shaped organ with a long tongue- 
like projection which extends forward almost to the optic chiasma. 
He found no cavity within it. In Acanthias and Mustelus the 
hypophysis is larger than in Torpedo and Scyllium. 
Sanders (’86) studied the central nervous system of Scyllium 
and Acanthias. He stated that the hypophysis is attached to 
the infundibulum by a glandular tube which lies between the 
inferior lobes. In a drawing of the brain of Acanthias (lateral 
view) he figured the hypophysis as lying caudal to the inferior 
lobes of the mesencephalon. 
In 1892 Edinger described the mid-brain region. In Torpedo 
and Scyllium he found the hypophysis composed of tubules and 
cords of epithelium, among which are many blood vessels. He 
noted nerve fibers extending from the infundibular region ven- 
tralward into the hypophysis. 
Haller (’96) described in detail the structure of the hypophysis 
of a 20 cm. Mustelus. He stated that in the adult the glands 
of the head (superior) portion are tubular. Secretion and cell 
detritus are found in the lumina. He also described an opening 
in the base of the anterior lobe. This is found in the thin portion 
of the floor in the position of the original connection with the 
mouth, and connects the cavity of the hypophysis with the 
subdural space. 
Sterzi (’04) described the hypophysis in several selachians. 
He found the anterior part flattened dorso-ventrally, extending 
almost to the optic chiasma and containing a large cavity. 
The posterior part is separated from the remainder by con- 
nective tissue. A slender canal connects this to the anterior 
portion. The superior part is formed of anastomosing cords 
interlacing with sinusoids. The cords are formed of a periph- 
eral layer of columnar cells and an inner mass of polyhedral 
ones. The nuclei of the outer zone are rich in chromatin. The 
