414 KALPH FAUST SHANER 



fourth and fifth pouches and the postbranchial body form an 

 independent complex of three closely associated vesicles which 

 retain their epithelial character in later stages. My results 

 are essentially an amplification of Van Bemmelen's — a closer 

 analysis of the complexes arising from the third and fourth 

 pouches. The fifth pouch does not enter into the second com- 

 plex, as Van Bemmelen thought; the three vesicles composing it 

 are the dorsal and ventral outgrowths of the fourth pouch and 

 the postbranchial body. Johnson, in a very brief abstract, 

 notes the finding of an anterior thymus and anterior parathy- 

 reoid gland derived from the third pouch. He finds, however, 

 no posterior parathyreoid, and derives the posterior thymus 

 from the fifth pouch. Without knowledge fuller than an ab- 

 stract affords, it is difficult to determine the cause for John- 

 son's radical difference from the results of others, including my 

 own! The suppression of the fourth pouch and the full develop- 

 ment of the third and fifth would be a very unusual procedure. 

 The fragmentary report of Von Alten's work, given out by 

 Keibel after his pupil 's untimely death, does not extend beyond 

 the earhest stages. Von Alten finds five pouches, notes the 

 branchial placodes, and is inchned to consider the postbranchial 

 body a rudimentary fifth pouch. The last is, of course, a very 

 debatable question. I have given my reasons for rejecting this 

 interpretation elsewhere. 



No one writer has given a complete account of the branchial 

 derivatives in the adult turtle. Van Bemmelen ( '88) found the 

 adult anterior thymus and enclosed parathyreoid gland, and 

 discovered the aortic body. Beyond noting the epithelial charac- 

 ter of the last, he gives no further details. Afanassiew had 

 previously described the anterior thymus and enclosed 'carotid 

 body,' but overlooked the aortic body. On the other hand, 

 Thompson gives a very complete and well-illustrated account 

 of the aortic body in several species. She is the first to recog- 

 nize that, although a parathyreoid gland and postbranchial 

 body are the chief constituents of the aortic body, a small thymus 

 is generally present. Doyen finds the posterior parathyreoid 

 gland in the 'African tortoise.' His photomicrograph shows 



