4.76 RICHARD ASSHETON. 
certain distinct currents are produced thereby. Posteriorly, 
however, the ciliation is very scattered and feeble, and pro- 
duces no distinct flowing. 
Figs. 19 and 20 represent the lateral and ventral views of 
such an embryo. 
Over the dorsal and lateral surfaces there is a steady flow 
along the longitudinal axis of the embryo. Ventrally there is 
an especially rapid stream from the pre-oral region into the 
stomodeal pit, whence the water passes over the ventral wall 
of the embryo. The water from the lateral parts of the pre- 
oral area also flows towards the stomodzal pit, and then passes 
outwards and upwards towards the locality of the branchial 
arches. This current is more markedly present in a 6-mm, 
newt, as shown in fig. 22. 
In fig. 21 a lateral view is given, showing how the action of 
the cilia at this stage is to bring as much water as possible 
into one stream, which may be said to start about the position 
of the olfactory epithelium and skirt below the “ balancers ” 
(M.), and pass very rapidly over the spots where the external 
gill-filaments are about to develop. Water from the dorsal 
region is also swept down into this same stream. 
Over the posterior end of the embryo the ciliation is very 
slight. After the complete development of the external gills 
the ciliation over the greater part of the body becomes less 
active, and by the time the newt tadpole measures 16 mm. it 
has entirely disappeared excepting upon the gill-filaments 
themselves. 
The special ciliated region which is present in the frog be- 
hind the stomodeum in connection with the cement-glands is 
absent in the newt. Ciliated cells occur here as elsewhere, 
but no special streams are produced. The balancers, which 
are placed much further from the mid-ventral line than are the 
cement-glands of the frog, are similar to the cement-glands in 
that at their extreme points there are cells which secrete a 
similar sticky cement by which the young newt can attach 
itself to weeds. They differ in that the cement-glands, which 
are very much smaller, are borne upon processes of the body- 
