STZ, CHIKANOSUKE OGAWA 
1. Elastic fibers in Amphibia 
Diemyctylus pyrrhogaster. The elastic fibers are fine and form 
thick nets in submucous layer of the lung wall. These fibers 
are seen in two layers: the inner, which is circular and rich in 
elastic fibers, the outer which is in the main longitudinal and less 
rich in fibers. In both layers the fibers are not wavy, but run 
straight, forming the nets by ramifications and anastomoses. 
The thickness of the net is uniform throughout the lung except 
for a slight increase in strands around the blood-vessels other 
than capillaries. According to Oppel, the elastic fibers are more 
strongly developed in the muscle bundles of the lung of Triton 
alpestris, while in the lung of Diemyctylus the muscle fibers do 
not present bundles and these fibers do not contain elastic tissue. 
Oppel, moreover, states that in his Triton the outer layer 
(which he calls subserous) is stronger than the inner, while in 
Diemyctylus the reverse is the case. 
Rana nigromaculata. The elastic fibers of this animal are 
seen in the connective tissue of the alveoli as well as the wall of 
the lung. Thus in the septa the fibers are situated between the 
two capillary nets. Here we see that, differing from Diemycty- 
lus, elastic fibers take two distributions, one forms bundles which 
mix with muscle fibers, while the other has no relation to muscle 
tissue. 
In general the elastic fibers in Rana form looser nets than in 
Diemyctylus. Since the muscle fibers in the free edges of the 
septa are well developed, the elastic fibers are also well developed, 
especially just around the muscle bundles. The interweaving 
nature of the fibers which accompany the muscle bundles is the 
same as described in the chapter dealing with muscle fibers. 
Megalobatrachus japonicus. he elastic fibers seen in the 
connective tissue in the outer part of the lung are abundant and 
are coarser than in Diemyctylus: Although not as evident as 
in Diemyctylus, there are two layers, the outer consisting of 
longitudinal fibers, the inner of fibers of irregular course.. In 
general the fibers differ from those in Diemyctylus by ramifying 
and anastomosing more frequently and resemble them by being 
present in muscle fibers. 
