1120 General Notes. 
gnaths the stigmata are placed beneath or even in the coxal joints 
of the legs. 
In the genital organs the most marked differences occur. In the 
Chilognaths both ovary and testis consist of a simple sac-like 
organ, communicating by a double oviduct or vas deferens with 
the paired genital openings situated one on either side, at or behind 
the bases of the second pair of legs. In the Chilopods, on the 
other hand, the sexual organs possess but a single efferent duet, and 
this opens in the middle line of the posterior end of the body just 
below and in front of the anus. In the Chilognaths both ovary 
and testis are below the intestine, a position indicating inferiority. 
In the Chilopods they have their origin in the same position which 
they permanently occupy in the other group, but with development 
they come to occupy a place above the alimentary tract. e 
spermatozoa, in the Chilognaths, are quiescent; in the Chiolopods 
they are active. The position and character of the genital ducts in 
the Chilognaths is such as to lead to the supposition that here, as in 
many other metameric forms, they may have had their origin in a 
pair of segmental organs which have become specialised for carrying 
away the generative products. Heathcote’s account of the develop- 
ment of the generative glands of Iulus certainly does not oppose this 
view. Inthe Chilopods, on the contrary, there is nothing in the 
adult structure (we know nothing of the development) which 
would even suggest such an origin for the generative ducts. 
_ Now these points are all of considerable morphological import- 
ance, as we must, for instance, go far back in the ancestry to find a 
condition from which we can derive the two types of generative 
organs mentioned above, and exactly what structure that ancestor 
must have had it is difficult to say. It is, however, clearly impossi- 
ble to derive either condition occurring in the Myriapods from the 
er. : 
_. + If, however, we turn to existing forms to find the nearest relations 
of either group, our search is to a certain extent easy, for the next of 
kin of the Chilopods are certainly found in the Hexapoda. | 
all those points where Chilopods and Chilognaths disagree, the 
Chilopods and Hexapods are in harmony. Both have the same 
number of mouth-parts; both have the appendages segmentally } 
_ arranged ; the spiracles the same, while there is no little similarity _ 
between genital organs, ducts,and openings. Indeed taking Scolopen- 
_ drella into consideration, it seems impossible to frame a definition 
which will serve to separate all the Hexapods from the vere 2" 
It would seem then that we should unite both Chilopods and Hex- 
apods in one class. 
_ With regard to the Chilognaths, it seems not so easy to trace — 
: relationships. So far as is apparent, they form a group by them- — 
= Selves with no nearer affinities than those presented by the Anne- 
