62 HYPOPHYSIS-^OVARY-^OVIPOSITOR II 



lobus tuberalis is completely free and the lobus anterior 

 relatively free, there is also a more intimate connection 

 between the lobus intermedins and the lobus posterior than 

 between the lobus intermedius and the lobus anterior 

 (Fig. 51B, X). As is evident from the neurocrinia (p. 71) 

 and the blood supply (p. 62), there is not only a topo- 

 graphical, but also a functional relation between the two 

 lobes. Thus, for example, the lobus intermedius cells in 

 Anomalops are placed like a thin layer of epithelium upon 

 the voluminous, richly vascular body of the lobus posterior. 



§ 3. THE BLOOD SUPPLY OF THE HYPOPHYSIS IN 

 RHODEUS AMARUS 



Since the hypophysis both prepares and receives chemical 

 stimulating substances, an investigation into the blood supply 

 seemed important, the more so because, so far as fishes are 

 concerned, we have as yet no knowledge bearing upon this 

 question. From serial sections, three of which were taken at 

 right angles with each other, DuDOK DE WiT and Bret- 

 SCHNEIDER have reconstructed the circulatory system of the 

 hypophysis of the bitterling. 



a. Position of the hypophysis. 



As may be seen from Fig. 52, the narrow stalk of the hypo- 

 physis pierces the dural "diaphragm", which lies stretched 

 out in an opening of the primordial cranium. The tunnel- 

 like space found below this is the myodome of the cra- 

 nium, in which the hypophysis is freely suspended. The 

 extrinsic eye muscles and the bloodvessels lie in the fat and 

 the connective tissue. At the back, the myodome is closed 

 only at the level of the auditory capsule and in front by a 

 thick connective tissue septum. 



b. The arterial blood supply. 



The hypophysis receives arterial blood from the two internal 



carotids (a), which arise from an open circulus cephalicus. 



Immediately behind the branching-off of the arteria 



orbitalis (e) the carotid artery presents an appearance 



