566 
J. S. KINGSLEY. 
position. Most of the post-oral parts were concerned in 
respiration. 
In the foregoing I have taken no account of Pauropus and 
the Myriapods, the facts concerning them being not yet well 
enough known. It seems possible that they have no connec- 
tion with the Hexapods. The structure and relationship of 
the trachea, the ventral position of the genital glands, the 
mouth parts, the innervation of the antennae, the existence of 
segmental organs in Peripatus and their possible homologues 
in the foramina repugnatoria of the Myriapods, all need 
to be taken into consideration in this connection. 
I do not intend to defend in extenso these points at the 
present time; a few explanatory notes may, however, be of 
value. The relationship of the oviducts to the exterior in the 
Arthropods seems to point to the conclusion that here, as in 
many other animals, they are modified segmental organs. The 
positions in which these ducts empty would then warrant the 
conclusions given above regarding the relationships of the 
segmental organs. Several authorities (especially Grobben, 
79 and ; 81 b ) have pointed out that the genital glands of 
Arthropods are ventral in origin, and that they later assume a 
dorsal position. This author also points out, as an indication 
of inferiority, that they permanently retain a ventral position 
in Peripatus and Myriapods. 
Whether the first pair of appendages in the ancestral 
Arthropod played a part in eating is uncertain, though the 
facts that it now does so in the Hexapods, Myriapods, and 
Peripatus, and that in the other groups it at first has a post- 
oral position is in its favor. In Limulus, as in Apus, and in 
the Nauplii of various Crustacea, the basal joints of at least 
two pairs behind the first are so employed, and in the two 
forms first mentioned the series is extended further. In all it 
is the basal joint which is so employed, and in the young of 
some and the adults of others the distal portion is used for 
ambulatory purposes. 
Note. — Since this article was sent to the printer several papers have 
appeared which have more or less bearing on the subjects here discussed, though 
