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number of solitary glands, most of which are arranged in a rather distinct row (cf. fig. 6) and
a number situated irregularly; in the specimens investigated by me from 105 to 143 of these
glands were found on each valve; in most cases they were quite absent inside the rostrum and
along the dorsal third or half of the posterior margin of the Shell. In preserved material one
often sees hyaline fibres attached to these glandular exits; these are certainly solidified sécrétions.
Outside these glands there are a small number of solitary glands, some opening inside and others
outside the margin of the shell. The joined part of the lamellae is narrow. The outer lamella
is not specially thin and is moderately strongly calcified; this lamella was brittle in a number
of the specimens investigated by me.
First antenna: — This has five joints*. Between the first and second joint there
is in most cases a rather distinct ventrally open knee. The proportion between the lengths
of the joints seems fairly constant and is about as follows:
I : II : III : IV : V
The first joint has not disto-ventrally any verruciform process as in (all?) the males
of the genus Euconchoecia (this is presumably a genus character). The dorsal bristle of the second
joint is situated at about the middle of the joint; it is powerful, has short hairs and is
compar-ativelylong, being in most cases equal to the total length of the four distal joints of this antenna.
The bristles of the two distal joints vary somewhat in length. The e-bristle of the end joint is
about two or three times as long as this limb and is sometimes about as long as, sometimes
a little longer than, sometimes considerably shorter than twice the length of the a—d-bristles;
the e-bristle is only slightly or sometimes not at all widened along its distal half, and is furnished
with only a few hairs. All the joints are quite bare.
Second antenna: — P r o t o p o d i t e: This is of moderate size; in specimens
with shells about 1,4—1,5 mm. long it attained a length of about 0,6—0,7 mm. Its
distallateral verruciform process varies somewhat in shape; it is often of the type reproduced in
fig. 9. Exopodite: This is rather slightly shorter than the protopodite. The proportion
between the lengths of the exopodite and the protopodite is about 6:7. The first joint is relatively
long; the relation between its length and the total length of the eight distal joints is about 4:2
or even 5:2. The eighth joint is rather well developed and almost as long as the immediately
preceding joints. The first joint is bare; its ventero-distal bristle is fairly straight and is about
as long as or somewhat longer than the second joint, annulated, bare or sparselv furnished with
exceedingly short hairs. The natatory bristles on the second to the eight joints are all of about
the same length — the distal ones are only slightly shorter than the proximal ones and about
one and a third or one and a half times as long as the exopodite; their distal parts, about a fifth
or a sixth of the length of the bristles, are bare, hyaline, but very slightly or not at all widened
in the shape of a lancet (sensory organs); they are furnished with relatively long natatory hairs
almost down to the base. The end joint has three bristles: One of these is sparsely furnished
with short, fine hairs or is bare, and is about as long as the total length of the four distal
joints, the second is of the same type, but is, in most cases, somewhat longer than the eight distal
* For Ch. Juday’s statement about six joints on tilis antenna see p. 600 below. For the explanation of the
third joint see p. 511 above.
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