216 ALICE L. EMBLETON ON A NEW 
attached to the abdomen of the female. Kossmann says the 
female is 1°7 mm. and the male 0°6 mm. in length. Claus repeats 
Philippi’s measurements of 3 line for the female, the male being 
but half as long. In this new Japanese form, however, the 
sexes show little (if any) difference in size, and I have found no 
single instance of the male being attached to the female. Sexual 
dimorphism between the female and male is not very apparent, 
only being manifest on a closer examination of the more minute 
parts; none of the adult females have egg-sacs, as these would 
doubtless only be present for a very short period, which may 
explain their absence from my specimens if they were collected 
at a time of year when the sacs are not developed. Thus, a 
general description of the animal applies equally to the two 
Sexes. 
The body is flattened dorso-veutrally, the carapace being, 
however, slightly arched ahove. Dorsally, the outlines of the 
segments are quite clear, there being four well-marked thoracic 
segments behind the head; following on this is the small 
tapering abdomen made up of 6 segments, the last two of which 
are divided and constitute the furce, each limb carrying an inner 
long and an outer short seta (Pl. 21. figs. 1, 2,3, 4). In the 
adult female the first three abdominal segments are fused, and in 
this fused region the paired genital pores open ventrally (PI. 21. 
fig. 2, 9.). 
There are no eyes, which may be an adaptation to its habitat. 
Canu figures Hersiliodes as being destitute of. eyes, though the 
other two genera possess them paired and well-developed. 
Anteriorly the carapace curves down, as is seen on looking at 
the creature from below (Pl. 21. figs. 2, 3). Notches in this 
in-turned edge occur to allow for the free movement of the first 
antenne, between the bases of which the carapace bears at its 
edge two short spines (not, however, in the adult male, though 
present in its earlier stages). 
Tn order to investigate the appendages, it was necessary to get 
separate dissections of each. The animal being so small and its 
chitinous parts being so brittle, I experienced considerable 
difficulty in obtaining satisfactory preparations. The best results 
were secured when I boiled the material in strong potash for 
some minutes, wasbing it thoroughly in water before staining 
with safranin. Specimens treated in this way showed most of the 
hard parts with great clearness, though the safranin being an 
aniline dye, fades in glycerine, with the result that the mountings 
