379 
than broad; the flagellum is nearly three times longer than the 
branch and somewhat longer than the breadth of the head. The 
lower branch is slightly more than half as long as the upper 
one, more than two and a half times longer than broad, consider- 
ably widening from the base towards the anterior flagellum, and 
its anterior angle is deeply and very obliquely cut off. The po- 
sterior flagellum is nearly three fourths as long as that on the upper 
branch and two and a half times longer than the anterior flagellum. 
All three flagella are very slender, cylindrical. The globulus is 
very small, its transverse diameter considerably shorter than that 
of the upper branch. 
Trunk (fig. 16). Very elongate and slender. — The fifth pair 
of tactile setæ slightly more than one half longer than the breadth 
of the segment, rather slender, with exceedingly short pubescence. 
The fourth pair is about four fifths as long as the fifth and some- 
what thinner; the third pair is only a little shorter than the fourth, 
cylindrical almost. from the base to the middle and from thence 
tapering, with the pubescence longer and more conspicuous than 
on the posterior pairs. — The four posterior setæ on the. penulti- 
mate segment are long, slightly tapering; the setæ on the last seg- 
ment are very long, slender and tapering, half as long as the po- 
sterior breadth of the segment. 
Anal Segment (pl. IV, fig. 1b and 10; pl. III, fig. 5a). The 
tergum is posteriorly very broadly rounded, almost cut off; its three 
pairs of slender, tapering setæ are arranged nearly as in P. danicus, 
but they are still longer; the submedian pair is a little shorter 
than the intermediate setæ, while the lateral setæ are one half 
longer than the intermediate ones and nearly as long as the breadth 
of the segment. — The styli (fig. 16) are rather thick and cla- 
vate, nearly thråe times longer than broad and even lønger than 
the anal plate without its branches. — The sternum with the po- 
sterior setæ cylindrical and somewhat shorter than the submedian 
dorsal pair: the lateral setæ are considerably shorter than the po- 
sterior pair, the anterior setæ are very short, inserted rather near 
