[ *3* j 
organs, a larger and a fmaller one, which 
are placed on each fide, and feparated 
from one another by a membrane. The 
large pair occupy the whole lower or an¬ 
terior, and alfo the lateral part of the 
body, and run from the abdomen to near 
the end of the tail. It is broad eft at the 
end next to the head of the animal, be¬ 
comes gradually narrower towards the tail, 
and ends almoft in a point. 
Thefe two organs are feparated from 
one another at the upper part of the mufcles 
of the backj below that, and towards the 
middle, they are feparated by the middle 
partition. Their union with the parts to 
which they are attached is in general by a 
loofe, but pretty ftrong, cellular mem¬ 
brane, except at the partition, to which 
they are joined fo clofe as to be almoft 
infeparable. 
Thefe organs con lift of fepta and crofs# 
divifions. The fepta are thin membranes, 
K 2 which 
