510 HERBERT E. DURHAM. 
that it deserves the name of neurenteric canal in the strict 
sense of the words. 
I quite agree with Mr. Spencer that the figure drawn by 
Gotte {vide Balfour, ‘Comp. Embryol.,’ vol. ii, p. 107) of a 
Bombinator embryo will not apply to Rana embryos; 
first, because the canal does not persist to so late a stage as 
that figured; and secondly, because the arrangement of the 
parts is quite different to any that I have seen in Rana; and 
thirdly, because the anus is not represented as open; but this 
is not of importance as the section may not be in the right 
plane for the actual anal aperture. 
I agree with Mr. Spencer that the blastopore persists as the 
anus in Rana. I may add, however, that I have one series of 
sections of an embryo Rana in which there is no blastoporal 
opening whatever, but I am inclined to regard this as patho- 
logical as I have so many other embryos which apparently are 
of the same age, and which possess a very well-marked aper- 
ture, with both the position and appearance of the blastopore. 
Figs. 1 and 2 are the posterior ends of median longitudinal 
sections of an embryo of Rana; of these, fig. 1 passes through 
the blastopore, while fig. 2 includes the communication 
between the neural and alimentary canals. 
Figs. 8, 4, and 5 are similar sections of another embryo; 
figs. 8 and 4 show the relations of the blastopore and the 
commencement of the neurenteric canal (dn) ; fig. 5 the latter 
canal and the posterior end of the neural canal. The neural 
canal (nc. in figs. 3 and 4) is continuous with that in fig. 5 
(also marked ne.). 
Fig. 6 is from a-transverse section at the level of the blasto- 
pore; it shows the cavities of the neural and neurenteric 
canals and of the blastopore. A few sections further towards 
the posterior end the lumen of the neural canal is seen to be 
continuous with that of the neurenteric canal, and further 
forwards the latter is connected with the main gut cavity. 
The broad part of the neurenteric canal remains, and is very 
obvious for some time after the closure of the actual com- 
munication with the neural canal. 
