588 AMPHIBIA. 
Muscular system.—The muscles are enswathed in con- 
nective tissue. They consist of bundles of striated fibres, 
and at their ends or at one of them they are usually con- 
tinued into’ tendons, 
which are more or 
less directly attached 
to parts of the skele- 
ton. 
For an account of 
the musculature of 
Vertebrate types, 
the student is re- 
ferred to the 
guides to practical 
work cited in the 
Appendix. 
Nervous system.— 
The brain, covered 
with a darkly pig- 
mented pia mater, 
has the usual five 
parts. 
The elongated 
cerebral hemi- 
spheres have 
“olfactory lobes” 
in front of them, 
and are con- 
nected by an- 
terior and 
ByMbne eof 
A 
Fic. 319.—Nervous system of frog.—After posterior com- 
Ecker. ee missures, and 
1-10, The cranial nerves ; oc., eyes; cvd., in front of 7 
optic chiasma; /o., optic’ tract’; syit., sympa- by a hint of a 
thetic system; #zsf., spinal cord; sé., spinal oF corpus cal- 
nerves. 
losum ” (?). 
The thalamencephalon gives origin dorsally to a pineal 
outgrowth. The pineal body lies outside the skull in 
the tadpole, but is partially atrophied in the adult, so 
that little more than the stalk is left. On the ventral 
side will be seen the chiasma or interlaced crossing of 
the optic nerves, and a tongue-shaped mass (the tuber 
