441 



the blood vessels, on each side an anterior prolongation of the sinus 

 stern alls appears, lymphoid cells are seen in the denser anterior 

 portion of the reticulum, and there results the C. propericardiale 

 as previously noticed (Figs, 5 and 6). 



Summary. 

 The so-called "ventraler Kiemenrest" (Maurer) of the frog is 

 not derived from any part of the wall of the branchial chamber. It 

 may be appropriately designated as "Pseudothyreoidea" (Mayer). The 

 pseudothyreoidea and Corpus propericardiale have essentially the 

 same structure, develope simultaneously, the arterial supply of the 

 two is from the same branch of the external carotid artery, the 

 ramus musculo -glandularis, their chief venous outlet is the 

 Vena pseudothyreoidea. Both originate in regions previously 

 occupied by portions of the basihyo-branchialis muscle of the 

 tadpole. 



I wish to express hereby my thanks to Geh. Hofrat Professor 

 WiEDERSHEiM for Ms kinduess in allowing me a table in the Ana- 

 tomisches Institut in Freiburg, and to Professor Gaupp for the use 

 of his most excellent preparations, and for his criticisms and helpful 

 suggestions. 



Literature. 



1) Babes, E. C, Researches on the minute structure of the thyroid 

 gland. Philos. Trans. Roy. Soc. London, Vol. 172, 1881. 



2) Carus, C. G., Lehrbuch der Zootomie, Leipzig 1818. 



3) DuGiis, A., Recherches sur I'osteologie et la myologie des Batraciens, 

 Paris 1834. 



4) Fleischl, E., Ueber den Bau der sog. Schilddrüse des Frosches. 

 Sitzungsber. d. K. Akad. d. Wissensch. Wien., math.-naturw. GL, 

 Bd. 57, L Abt., 1868. 



5) Gaupp, E., Ecker's und Wiedersheim's Anatomie des Frosches, 

 IL Abt., p. 385 u. 514; IIL Abt., 1. Hälfte, p. 220, Braunschweig 

 1899 und 1901. 



6) HuscHKE, E., Ueber die Umbildung des Darmkanals und der Kiemen 

 der Froschquappen. Isis von Oken, Bd. 1, 1826. 



7) Maurer, Fr., Schilddrüse, Thymus und Kiemenreste der Amphibien. 

 Morpholog. Jahrb., Bd. 13, 1888. 



8) Mayer, S., Zur Lehre von der Schilddrüse und Thymus bei den 

 Amphibien. Anat. Anz., Bd. 3, No. 4 u. 5, 1888. 



9; MtJLLER, W., Ueber die Entwickelung der Schilddrüse. Jenaische 



Zeitschr, f. Med. u. Naturw., Bd. 6, 1871. 

 10) Schulze, F. E., Ueber die inneren Kiemen der Batrachierlarven. 

 IL Mitteil. Abhandl. d. Königl. Preuß. Akad. d. Wissensch. zu 

 Berlin, 1892. 



