Bd. V: ii) 
THE ACARI. 
17 
7. Zercon tuberculatus nov. spec. 
(PL II, figs. 8, 13, 15 & 16, text-figs. 30 — 33.) 
Length 0,63 mm. Breadth o, 32 mm. 
Colour , yellowish-white. Shape of the body, elongated quadrangular, with slightly 
convex sides; the greatest width between coxæ II and III; at the anterior and the 
posterior end squared-rounded; the hind margin with 4 — 5 pairs of small, hyalin, 
conical tubercles (PL II, fig. 16). 
The dorsal side covered by a single, week shield, which in some places exhibits 
a net-like, scaly texture and by higher magnification is seen to be very finely 
striated transversally. Hairs rather scarce, becoming longer towards the posterior 
end. The hind margin provided with one pair of small median hairs and two pairs 
of long lateral hairs. 
Ventral side. 
Tritosternum with broad, almost 
cylindrical trunk, the anterior end 
square, with a median incision; the 
feathered slips very narrow, lanceo- 
late, a little more than three times 
as long as the trunk. Sternal shield 
(Text-fig. 30) very week, partly fin- 
ely punctured, posteriorly rounded, 
extending backwards as far as to 
the hind margin of coxae III, with 
three pairs of hairs. Ventral portion 
very soft, with four pairs of hairs, 
of which the posterior one is insert- 
ed near the postero-lateral angles 
of the body and extends far beyond 
the margin. 
Zercon tuberculatus Tgdh. nympha. 
Fig. 30. Ventral view. 30 x . Fig. 31. Hypostoma. 620 x . 
Fig. 32. Ambulacre III. 620 x . Fig. 33. Ambulacre I. 
620 x . 
Anal shield square-oval, with net- 
like texture, nearly contiguous with the 
hind margin, with three small hairs. 
Behind coxæ IV are indications of metapodial shields, finely punctured. 
Peritremata (PI. II fig. 13) very short, only twice as long as broad, situated 
outside coxæ IV. 
The epistorna (Text-fig. 31) triangular, with a long median projection; the out- 
lines of the sides divided in two concave parts, one more deep proximal and one 
more shallow distal. 
I038 / 07. Schwedische Südpolar-Expedition iqoi — 1903. 3 
