362 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



the tissue of the thyroid lobe, with which it is associated. 

 It is derived from the lateral thyroid anlage, and so from 

 the fourth branchial pouch. The other, the external 

 epithelial corpuscle (" Glandule thymique " of Simon) 

 always lies outside the thyroid lobe at a variable distance. 

 It arises in association with the thymus from the third 

 branchial pouch. 



I have described elsewheref a connection between the 

 cervical thymus and the thyroid lobe of the same side in 

 a foetal Macropus, in the form of a cord of cells uniting 

 the two organs. This suggests a relation of the former 

 organ to the thyroid rather than to the thymus organ in 

 the mediastinal space. It is possibly the case that the 

 cervical thymus may correspond to one of the epithelial 

 corpuscles, though its minute structure does not resemble 

 that of the latter (which, however, may be very variable), 

 and its superficial position is against this view. The 

 nature of the structure can be only a matter of conjecture, 

 however, until its development is made known. 



f JourD. Linnean Soc, London, vol. xxvi., p. 546. 



