159 
than in the former species. The last joint of the maxillipeds and the terminal spine on the 
penultimate joint in the specimen from D. levis are not very different from S. dispar, and 
distally much less expanded than in the specimen from D. cornuta (fig. 42), but this difference 
is scarcely of any value. The trunk is naked. The genital area, in both specimens, is a 
rather small, transverse plate of irregular shape, and for the most part very thin, which, in 
the specimen from D. cornuta (fig.4e) is about twice as broad as long, on the whole remin- 
ding of a rectangle; in the specimen from D. /@vis (fig. 4d) it is comparatively a good deal 
longer, somewhat heart-shaped, having a concave front margin, and an irregular, lobed 
posterior margin; in both specimens the genital apertures are middle-sized, somewhat oblique 
and curved, anteriorly not far apart; the area is naked, caudal stylets wanting. (The 
differences in the shape of the genital areas are indeed very considerable, but in both spe- 
cimens the plate is so irregularly shaped, so unsymmetrical and so feebly chitinised, that I 
do not think its shape is of any importance; on the contrary, I expect that other specimens 
of this species will exhibit other shapes of the plate. 
MALE. In proportion to the female, it almost exceeds medium size (fig. 4b : fig. 4a); 
the specimen from D. levis (fig. 4b and fig. la—1b) is -29 mm. long, the one from D. cornuta 
(fig. le—1d) -31mm. long. The specimen from D. levis is — seen from the side (fig. La) 
— considerably thicker than the other specimen (fig. 1d), however, this thickness seems to 
be due to a swelling of the body which is scarcely normal. Otherwise there are no other 
differences between the two specimens than those which may be detected in comparing 
fig. 1 b and fig. 1 ¢. viz. some slight deviations in the anterior part of the front and in the 
hai-covering in front of the antennule. -— Seen from below, it bears great resemblance to 
S. dispar, but the greatest breadth of the body lies more backward, and it deviates especially 
in the somewhat different shape of the front, and in the equipment of the maxille and of 
the sub-median skeleton. The distance from the antennule to the narrowest part of the 
frontal plate is shorter than in S. dispar; the expanded distal part is not circular, but 
considerably broader than long, limited to the front by a regular arc, the third of a circle, 
and decorated with processes as in S. dispar; the lateral angles are almost rectangular, 
and posteriorly the dilated part is limited by oblique lines. From the base of this expansion, 
backward along the lateral margin itself, runs a pretty good-sized keel (fig. 1b, y), which is 
also limited by an are of a circle, and which is armed with setaceous processes similar to those 
of the median expansion. In the middle of the ventral side of the expansion we find the 
small chitinous ring mentioned in the description of S. dispar, but in S. insignis the four 
processes are prolonged and meet in the centre so as to form a cross within the ring. 
Antennulee, mouth and maxillule nearly as in S. dispar. Maxille small; their basal joint 
has on its posterior side proximally a row of tolerably small, rather clumsy, processes 
directed backward, distally some much smaller processes; the third joint is well set off and 
acute. Basal joint of the maxillipeds scarcely as long as in S. dispar, its anterior side 
furnished with several rows of hairs; the other joimts nearly as in the preceding species. 
