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somewhat rnedially on tlie claw, continue in most cases right ont to the point of the claw and run
together proximally in most cases in the way shown in fig. 34 of Conchoecia symmetrica. The
proximal ones of these secondary spines are moderately strong or rather weak, the others
diminish gradually in size and strength the more distally they are situated. The lamellae are
often furnished with groups of rather short, rather soft or stiff hairs; on the other hand there
are no spines and bristles at all. Behind the furcal claws there is often an unpaired, short-haired,
rather weak, moderately long bristle.
Ali ni en ta r y organs:* — These are subject to only rather slight variation in
this group. Contrary to the Cypridiniformes there is always a very well defined a t r i u m, which ’
is fairly well closed below, in front and at the back. This atrium is bounded at the back
exclus-ively by the somewhat rounded (when seen from below wedge-shaped; cf. fig. 35 of Conchoecia
symmetrica in the present work) paragnates, which are always well developed. These have
on the ventral side some, in most cases four, rows of fine hairs running almost parallel to each
other and along the inner margin a row of hairs that are in most cases sti li and powerful. The
paragnates are attached on each side of the weakly arched under lip. The u p p e r 1 i p is large
and helmet-shaped and is attached to the under lip by means of chitinous lists. Between the
upper lip and the paragnates there is on each side of the mouth a rather deep indentation ; see
fig. 36 of Conchoecia symmetrica below; the pars incisiva of the coxale of the mandible
penetrates into this indentation; ci. G. W. Müller, 1894, pi. 1, figs. 18 and 19. The
postero-ventral part of the upper lip is somewhat lamellifoim; cf. G. W. Müller, 1894, pi. 37,
fig. 28 ; the rather strongly chitinized back edge of this part varies rather considera bly in type in
the different genera, but is always furnished on both sides on the middle part with a row of more
or less powerful hairs. The inside of this part has at about the middle two transverse rows
of stiff and rather powerful hairs and groups of short and exceedingly fine hairs. On the ventral
side of the upper lip numerous unicellular glands emerge, the glands of the upper lip; cf. G. IV.
MÜLLER, 1894, pi. 37, ■fig. 28; in addition there is a gland, in most cases extensive, with its
exit in the atrium; cf. the figure just mentioned. The oesophagus is rather long, with strong
muscles, and is bent evenly and moderately strongly backwards; see G. W. Müller, 1894,
pi. 35, fig. 16. The stomach is large, oval and is furnished on each side of the aperture of the
oesophagus with a rounded or rather elongated hepatic appendage, the lumen of which opens
into the stomach with a rather narrow canal. The rectum is very short and emerges in front
of the furca. No parts of the digestive organs ever penetrate between the lamellae of the shell.
Sexual organs: — Male: — The testes are paired, consisting of two
bagshaped oval bodies. From each of these there issues a rather short canal, the vas deferens,
which is very much widened in mature specimens and which is often even more voluminous
than the testes; cf. G. W. Müller, 1894, jpl. 38, fig. 19. The vasa deferentia are joined
inside the penis to an unpaired passage, which continues into the penis and emerges at its point. ,
F e ma le: — The ovaries, like the testes, are paired and are situated posteriorly in the body;
* The description of these organs given in this work is for the most part taken from G. W. Müller’s large
mono-graph, 1894 (pp. 119 and 120). This description, which seems lo be satisfaclory in a treatment of the systématisation
of tliis group, must, however, be added to fairly considerably. I hope to have an opportunity of giving a detailed
description of the structure and mechanism of these organs in a subséquent work.
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