124 W. BALDWIN SPENCER. 
between tae neural and alimentary canals, whilst the anus was 
subsequently formed as a proctodeum. 
Miss Johnson,! however, has shown that the neural folds do 
not thus enclose the blastopore in Triton, but that in this form 
it remains open and forms the permanent anus. 
Some little time previously Oskar Schulze published an 
account of his investigations with regard to the early develop- 
ment of Batrachians, and his paper is accompanied by a careful 
series of drawings, which, however, consist exclusively (save 
one small diagrammatic section) of external views of Rana 
fusca. 
He states? that the blastopore closes up, and that the anus 
is formed as a proctodeum very closely behind the posterior 
end of the neural folds. 
As before said, however, he figures no sections, and more 
lately an investigation of the egg of Rana temporaria, both 
by means of external views and of numerous series of consecu- 
tive sections, has given me a very different result, and one 
which differs also in important details from that described by 
Miss Johnson for Triton. 
The neural folds, as is well known, stretch back on the dorsal 
surface as far as the blastopore, and though but very slightly 
raised in this part they appear to pass round and join each 
other behind, as seen in figs. 2 and 3. 
Figs. 1, 2, and 3 show different stages during the growth of 
the folds, and in the last of these they are seen to have met, 
though the line of union is distinctly marked, and—most 
important—the blastopore is not enclosed. 
So far the account agrees with that of Gotte for Bombinator, 
the figures from which are copied in Balfour’s ‘Embryology.’ 
When this stage has been reached, however, according to 
Gitte, and after the blastopore has remained open to the ex- 
terior for some little time, the neural folds continue to grow 
and enclose it, whilst still later a proctodeeum is formed some 
distance anterior to this upon the ventral surface. 
1 * Quart. Journ. Mic. Sci.,’ Oct., 1884. 
2? « Archiv. fiir Mikr, Anat.,? Oct., 1883, part i. 
