PHARYNGEAL DERIVATIVES OF AMBLYSTOMA 659 



branchial ' body and interprets it as a structure derived from the 

 branchial, rather than from the postbranchial region of the 

 pharynx. 



At the Leipzig meeting of the Anatomische Gesellschaft ('11), 

 Maurer defends his view in his discussion with Rabl in the fol- 

 lowing way (p. 161), "Wahrend die von mir eingefiihrte Bezeich- 

 nung ' Epithelkorperchen ' sich gans eingebiirgert hat, ist die 

 Bezeichnung ' postbranchialer Korper' in die des ultimobran- 

 chialen Korpers umgeiindert worden. Ich kann diese Aenderung 

 nicht fiir gliicklich halten. Es ist das betreffende Organ bei alien 

 Wirbeltieren hinter der letzten Kiemenspalte vorhanden und 

 zeigt aufsteigend eine forts chreitende Weiterbildung, im Gegen- 

 satz su den Schlundspalten, die ganz schwinden. Es ist also das 

 Gebilde etwas von den Schlundspalten Verschiedenes und liegt 

 immer hinter der letzten Schlundspalte, darum ist es weniger 

 priijudizierend, wenn man es als postbranchialen Korper 

 bezeichnet." 



The most recent contribution on the structure is that of Kings- 

 bury ('14), who, although studying its development in mammals, 

 especially man, gives a discussion of its significance and homology 

 in the other vertebrates. He says, p. 609, ' 'Three points remain 

 indefinite — (1) its origin — whether it arises from branchial or post- 

 branchial region of the pharynx. Dependent upon the answer to 

 this question is the decision as to its designation as ultimobran- 

 chial, telobranchial, or postbranchial. (2) Its fate; whether — ■ 

 it persists within the thyreoid — (3) its value and interpretation 

 as an organ or structure." He gives Grosser's v!ew (a ductless 

 gland which has become rudimentary), and objects to this on two 

 points, namely: (1) that, ''with the exception of the ultimo- 

 branchial body in birds, no gland has been found in the forms 

 below the mammals with which the ultimobranchial body may be 

 homologized," and (2), "that the ultimobranchial bodies — if we 

 use that term — of the different classes of vertebrates cannot 

 themselves be directly homologized." He then cites Greil ('05, 

 anurans), Tandler ('09, man) and Grosser ('10, man), where all 

 agree that it is a derivative of a gill-pouch — the first that of the 

 sixth pouch, and the two latter that of the fifth pouch. ' 'It is 



