272 WILBUB WILLIS SWINGLE 
3. Synapsis 
This question needs little discussion here, considering the beau- 
tiful work of Janssens ('05), Janssens and Willems ('08), the 
Schreiners ('06), and Snook and Long ('14) on various amphib- 
ian types. The conditions in Rana catesbeiana larvae are essen- 
tially similar to those described by these works for the urodeles. 
Some of the earliest observations on the problems of synapsis 
were made on amphibian material, chiefly urodeles, and an end to 
end conjugation of chromosomes or telosnapsis was generally 
conceded to occur. Janssens ('05), working with Batracoseps, 
demonstrated parasynapsis, and later, working in collaboration 
with Willems, showed this to be true of the anuran Alytes. Wil- 
son ('12) after a study of Janssen's material, agrees with this 
author regarding parasynapsis in Batracoseps. Montgomery 
('11) who previously ('03) had described telosynapsis in urodeles, 
reversed his earher opinion and states (p. 753) : ''During the past 
year I have also convinced myself of the occurrence of parasyn- 
desis in Plethodon, such as Janssens had described for this object 
and the Schreiners for Salamandra." Snook and Long ('14) 
describe the same kind of evidence for parasynapsis in Aneides 
lugubris as that presented by Janssens and the Schreiners. 
It is interesting to note that King ('07) denies the existence of 
parasynapsis for Bufo lentiginosus, and states that telosynapsis 
is the method of chromosome pairing in this form. King regards 
the period of synapsis in Bufo as occurring coincidently with 
synizesis — a condition now generally regarded as an artifact, at 
any rate in Amphibia. The tetrad chromosomes of the first 
maturation mitosis. King thinks, arise by transverse segmentation 
of the thick spireme. If this description of conditions in the toad 
is correct, then this form differs markedly from other amphibians. 
Recently, however, the writer has had an opportunity of examin- 
ing preparations of Bufo, and is convinced that parasynapsis 
occurs in this animal as the normal method of chromosome conju- 
gation. Amphitene stages are abundant in the material exam- 
ined by me, and this is the true period of synapsis in anurans 
(figs. 11, 12, 13, 36 to 38). 
