ENDOCRINE SYSTEM OF TYPHLOMOLGE RATHBUNI. 



309 



vesicles have a distinct epithelial lining and are hollow; they do 

 not contain colloid. In addition to this rudiment, Typhlomolge 

 5 possesses another one of sim- 

 ilar structure, located on the 

 same side but more median. It 

 is attached to the left side of the 

 muscle just ventral to the basi- 

 branchial and just anterior to 

 where the first gill arch connects 

 with the basibranchial. Thus it 

 has very nearly the same location 

 as the median rudiment of other 

 animals, but is displaced slightly 

 to the left side. Apparently the 

 primary median rudiment of this 

 animal split into two rudiments; 

 one of them, the left one, moved 

 into its normal position. The 



right One not Only failed to do SO, FIG. 6. Left lateral thyroid rudiment 



but was dragged along a short of Typhlomolge 2. x 340. 



distance by] the] left rudiment before complete separation was 



FIG. 7. Left thyroid rudiment of Typhlomolge 5. X 340. 



