316 DR. A. E, SHIPLEY ON | Mar. 16, 
are of about equal length, but the tibia is not so stout; distally 
it bears a pair of stout bristles, hardly movable, against which the 
tarsal claws work. There are other bristles on the tibia, and 
numerous hairs on all the articles. The tibia bears a single- 
jointed tarsus which carries a pair of very mobile claws. These 
claws are constantly being depressed, usually one at a time, and 
rub against the tibial bristles. The tarsus also carries numerous 
knobs, and between the base of the claws a pulvillus may be seen ; 
this in some cases is retracted. 
The female has no external organs of reproduction, but on the 
seventh segment of the male there are situated ventrally a couple 
of complicated gonapophyses which presumably are modified 
abdominal’ appendages. These are figured on Pl. XXXVIII. 
fig. 9, which gives an adequate idea of their complexity. 
Respiratory Systeno. 
The tracheal system of Goniodes opens on the exterior by seven 
pairs of stigmata. There may possibly have been more, but we 
could not detect them. The most anterior is the largest; it is 
situated close behind the first pair of legs and is very difficult 
to see. Snodgrass * has described one in a similar position in 
Menopon titan. From it a trachea passes inwards and gives off 
a twig to the second leg. Further on it divides, one stout branch 
running anteriorly into the head, where it divides into two, each 
splitting up into innumerable small branchlets supplying the 
organs in the head. From the main trachea the second branch 
passes backward, giving off a twig to the third pair of legs, and 
then runs backward through the abdomen as a main longitudinal 
trunk (Pl. XX XIX. fig. 11). 
The abdominal stigmata are twelve in number, there being a 
pair on the second to the seventh segment, both included. They 
lie on little eminences like a tee in a teeing-ground, situated 
about one-sixth of the body breadth from the edge, and from 
each is given off a short trachea which soon splits into two 
branches. Of these the posterior splits up into innumerable fine 
twigs, which supply the various organs of the segment, and the 
anterior runs almost straight into the longitudinal trunk, thus 
placing the system connected with one stigma in communication 
with all the others on the same sides of the body. By this means, 
if one stigma be blocked the organs it supplies are not deprived 
of air, but receive it from another system. The smaller tubes 
on each side pass across the middle line and seem to place the 
right and left systems in communication. In Menopon titan, 
according to Snodgrass, the right and left systems communicate 
by means of a large transverse trunk in the fourth abdominal 
segment. 
The spiral thickenings are well marked. 
* Loe. cit. 
