312 EDUARD UHLENHUTH. 



every specimen. Like other salamanders, Typlilomolge possesses 

 3 pairs of thymus glands; in one animal they were found fused 

 into two large glands, one on each side. This condition is fre- 

 quently met with in adult salamanders. 



The postbranchial body, although, on a whole, it resembles 

 this organ in other salamanders, shows certain peculiarities 

 (see Baldwin's paper J for a description of this organ). Its struc- 

 ture is very similar to that found in A. opacum; in particular, it 

 is found only on the left side. It is an epithelial structure of the 

 shape of a tube possessing, in places, epithelial diverticula. A 

 lumen is frequently absent, while in A. opacum and other Amby- 

 stomidae this organ possesses often a very condiserable lumen. 

 The cephalic end of the organ is located in the pharyngeal epithe- 

 lium with which it connects near the place where in Amby- 

 stomidae the Adit us laryngeus is situated. In the Ambystomidse 

 the posterior end of the organ is often very large as compared to 

 the thin duct-like anterior end and is located on the left side of 

 the pericardium, posterior to the fourth aortic arch. Frequently 

 it is closely attached to the pericardium and posterior wall of the 

 fourth aortic arch. In Typhlomolge the fourth aortic arch is 

 missing; the postbranchial body attaches itself to the third aortic 

 arch. In some animals it reaches back to the heart and is found 

 attached to the pericardium. Its posterior end, however, does 

 not attain the size which this part is found to attain in Ambystoma. 

 Moreover, in some specimens the organ remains short, extending 

 backward only to the middle between pharynx and pericardium. 

 In these cases its posterior end becomes attached to the wall of 

 the third gill arch approximately half-way between the pericard- 

 ium and the entrance of the arch into the gill blade of the third 

 gill. It seems that the postbranchial body of Typhlomolge, 

 although it possesses, on the whole, the structure of the normal 

 organ of the Ambystomidae, shows sometimes signs of develop- 

 mental inhibition. 



The hypophysis was studied only in two animals and only in 

 transverse sections. Like the hypophysis of the Ambystomidae 2 

 it is composed of 4 parts, the pars anterior proper, the partes 

 tuberales, the pars intermedia and the pars nervosa. In the pars 



1 Baldwin, F. M.. Jour. Morph., ipiS.XXX., 605. 



2 Atwell, W. J., Anal. Record, 1921, XXII., 373. 



