380 CHIKANOSUKE OGAWA 
mouths or larger alveolar mouths do not join, but the rings of 
other adjacent alveolar mouths join together. The fiber rings 
of the alveolar mouths give off fine fibers to the alveolar walls. 
These fibers travel along the capillaries, ramifying, anastomosing, 
and forming loose nets. The reticular fibers of the blood-vessels 
and pleura give off fibers which anastomose with the fibers in 
the alveolar ducts and alveoli. 
Epimys (rat). The arrangement of the fibers in the lung of 
this animal is similar to that in Talpa and Vesperugo. The 
fibers, however, are a little coarser (fig. 33). As in the previous 
animals, each fiber ring around the mouths of the alveolar ducts 
and alveoli consists of one fiber, but in this case the fiber some- 
times splits and rejoins itself. Since the fiber rings of adjacent 
alveolar mouths are confluent in their common edge, triangular 
areas are sometimes formed between alveolar mouths. In this 
formation the rings send off finer ramifications to each other so 
that the rings here anastomose together. The fiber rings of the 
alveolar mouths again send off branches into the alveolar walls. 
The branches either leave the ring perpendicularly or in an 
oblique direction. It will be remembered that at the departure 
of elastic fibers from the ring there were several fibers which 
became confluent in a common fiber trunk, but the reticular 
fiber rings give off individual fibers. These vary in size; they 
are sometimes as thick as the fiber ring, sometimes branch 
immediately at departure, and sometimes they are exceedingly 
fine. In the alveolar walls the course of the fibers is more ir- 
regular than in the rings, and the fibers form close ramifications 
and many anastomoses. 
Cavia (guinea-pig). The reticular fibers in this animal appear 
to be coarser than those in the rat. The rings around the mouths 
of the alveolar ducts and alveoli consist of several fibers, or, in 
other words, they have many splittings. When a fiber branches 
from the ring, it occasionally starts as several fibers which later 
form a thick fiber. As in the rat, the branches going into the 
alveolar wall are of various thicknesses, but here well-marked 
thick fibers are formed which give off fine branches and which 
extend to the opposite side of the ring or reach into the adjacent 
