518 
G. L. GULLAND. 
from those which are autogenous? If autogenous pores can 
exist, is it not possible for the gonad to acquire continuous 
membranous connection with such a pore or pores, and so 
elaborate for itself an idio-gonaduct, which would have nothing 
to do with a nephridium ? 
These and similar questions present themselves for solution 
and must be answered before we can come to definite conclu- 
sions with regard to this unexplored question of the nature and 
significance of genital ducts. 
Finally, a point of great importance, which I propose to deal 
with more fully elsewhere, is the fact that the space in the 
connective tissue into which the young nephridium opens 
internally is not a blood-space. The blood-system in tbe 
larger Arthropoda is, I have recently ascertained, alto- 
gether distinct from the general system of lacunse of 
the connective tissue. These lacunse form a “lymphatic 
system/’ which contains a liquid distinct from the blood; they 
represent the coelom or body-cavity, and as such receive the 
internal openings of the nephridia. 
