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THE MORPHOLOGY OF THE TADPOLE OF XENOPUS 
LAEVIS. 
By T. F. Dbeyer, B.A., Ph.D. 
(Read August 19, 1914.) 
Material. — It was my intention to study the development in detail, 
but the Plathander (or, more correctly, Platanna), could not be got to 
oviposit in captivity and the tadpoles have been very scarce in ponds near 
Bloemfontein during the last two dry years. My youngest specimen 
should be about three years old, judging by particulars given by Leslie ; 
for it has no tentacles, no tail fins, and its head is not yet flattened dorso- 
ventrally. I can accordingly say nothing about the early development. 
Serial sections were prepared of five different stages, but as the head 
and branchial skeleton were considered of greatest importance, the 
series was not continued to the anus except in the youngest specimen. 
Two series ceased in the middle of the mesonephros and two were not 
taken beyond the head. 
The Platanna tadpoles have been described and beautifully figured by 
F. E. Beddard,t and those points raised by him will first be discussed. 
Sucker. — Beddard denies W. K. Parker's I statement that a sucker is 
not developed ; I can support Beddard, for my youngest specimen has a 
distinct sucker. 
Tentacles. — Boulenger, in a footnote to Leslie's already quoted paper, 
compares the tentacles of Xenopus to the balancers of Triton and 
Amblystoma ; Orr,§ according to Beddard, states that these balancers 
are the homologues of external gills belonging to the mandibular arch, 
and Beddard denies the homology of the tentacles and balancers, since the 
tentacles of the Xenopus tadpole are attached, on each side, to the 
* Leslie, Proc. of the Zoo. Soc, London, 1890. 
f Beddard, Proc. of the Zoo. Soc, London, 1894. 
+ Parker, Phil. Trans., vol. 166 (1877). 
§ Orr, Q.J.M.S., 1889, p. 295. 
