136 SALAMANDRADA. 
foot. At this stage a double dorsal line of minute brown 
spots may be seen. All these characters continue to be 
hourly developed ; and in the state which is represented at 
figures 4, 5, it quits its envelope, which has been continually 
becoming elongated to accord with the changing form of 
the embryo. On first issuing from the egg, it swims about, 
says Rusconi, without apparent consciousness of any im- 
pediments, striking against a leaf, or the sides of the vessel, 
and immediately adhering by its holders to the substance 
against which it happens to strike, and remains thus sus- 
pended for a time, as if asleep; and then, without any 
apparent excitement, swims off to another part. The 
developement of the young Tadpole, for such it must now 
be considered, progresses with considerable rapidity after 
its exclusion from the egg. In a fortnight, or three weeks, 
according to the temperature, it has acquired the condition 
exhibited in figures 6, 7. The branchiz now offer one of 
the most beautiful and elegant objects in nature, as well 
as one of the most interesting. Observed even with the 
nakéd eye, the leaf-like division of these organs present 
a most pleasing subject of contemplation ; but viewed in 
the microscope, the branchial circulation excites the great- 
est delight and surprise. The blood, which has now be- 
come red, ascends by the branchial arteries, and returns 
by the veins after having undergone the necessary change 
of decarbonization ; and the globules of the blood are seen 
accelerated by momentary jerks through the vessels. The 
transparent tail affords a beautiful example of the systemic 
circulation, as the former organs do of the respiratory ; 
and in both instances the transparency of the parts is such 
as to present no obstacle to the view. The eyes have now 
acquired their permanent character; the mouth has become 
terminal, and the anterior feet have acquired distinct digi- 
