400 E. A. BAUMGARTNER 
TABLE 1 
Terms used by the various investigators for the different parts of the elasmobranch 
hypophysis 
REGIONS OF THE HYPOPHYSIS 
OBSERVER MATERIAL ; 
Anterior Inferior Superior are 
Muller (71)i.c2e- -« Seymnus, Acan-}| Anterfor part Posterior (main part) 
thias (secondary ) 
alien! (96) ereseee Mustelus Superior sac Inferior sac Head 
Rossin (102) varios Torpedo Median _ lobe; | Antero-lateral Terminal lobe | Lateral 
antero-median diverticulum lobes 
diverticulum 
Stenzi(704) 5) seis Mustelus, Acan-| Anterior portion | Posterior portion] Superior portion 
thias 
Pettit: (06) )sevceaes Centro-scymnus | Anterior Median Posterior 
Burckhardt (’07)..} Seymnus Terminal lobe | Posterior lobe | Median lobe 
Gentes (’07)........| Torpedo Superior sac; | Inferiorsac Superior sae; 
anterior two- posterior one- 
thirds third 
JOFIS'(08)48 sas Mustelus Posterior Dorsal 
Sterz1! (209)e.-onee « Acanthias . | Perimeningeal Endocranial por-| Perimeningeal 
portion; ros- tion portion; dor- 
tral lobe sal lobe 
ebin'ey; (G41) peer Acanthias Juxta-neural part Distal part 
Stendell (’13)......| Heptanchus Main lobe Ventral sac of | Intermediate 
main lobe lobe 
Sterzi, Gentes, et 
A eereroahatsterstes areas Chromophilic portion Chromophobic 
portion 
MORPHOLOGY AND MORPHOGENESIS 
1. Description of the-hypophysis in the pup stage 
A description of the hypophysis in the pup stage may make 
clear the different parts of this organ. The formation of tubules 
has begun and the main portions or lobes are well formed at 
this time. 
The anterior lobe is a tongue-like process with two somewhat 
wider extremities; these are connected by a more slender middle 
part which is less than one-third of the entire length. There is 
a deep sulcus in the median ventral wall which extends from about 
the middle of the posterior extremity to near the end of the ante- 
rior extremity (fig. 1). Several other more or less regular furrows 
occur in the ventral surface of the anterior extremity. Two 
lateral constrictions separate the middle portion from the some- 
