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figs. 3 and 4). List: Inside the ventral margin of the sh eil this is more or less narrow, either
quite without bristles or only with a very few short ones. Inside the posterior margin of the
shell it is developed as a comparatively broad, hyaline lamella of uniform breadth and is provided
with a somewhat varying number of soft, hyaline, somewhat sword-shaped spines and with
a greater or less number of more or less short, fine, stiff, simple, bare bristles. The hyaline
spines are often so transparent that they cannot be seen with füll certainty, but their number
is easy to verify by means of the oval fixing areolae. It is also very difficult to establish their
length, for when the shell is looked at from the inside through the microscope, they are in most
cases directed towards the eye of the observer; the length that I have drawn in the accompanying
figures may often consequently be not quite correct. The latter part of the list is called in this
work, as will be seen below, „the spine-bearing list“ and forms a rather good species character,
as the number of hyaline spines and bristles is often rather different in different species, but
varies only slightly within each species. On the inside of the shell, on the rostrum, inside the
incisur and between the list and the margin of the shell tliere are a varying number of simple,
smoot-h, stiff bristles varying somewhat in length, which, on account of their number, length
and especially on account of their situation, provide good characters for the species. Between
the spine-bearing list and the posterior margin of the shell there is in a number of species a smaller
number of broad pores and close to these a greater or less number of fine ones; the former were,
at least in a number of cases, provided with low, hyaline pegs (which are protrusible?), the fine
ones do not seem to have either pegs or bristles. (The latter, the fine pores are called by
G. W. Müi jLER, 1894, p. 219, „kleine Spitzchen“, the inner medial bristles on the rostrum are,
on the other hand, called pores by the same author, ibid.) The shell is rather strongly calcified’.
The forms are moderately large.
Male: — This differs from that of the female as a rule by its greater length, though
sometimes the female may be somewhat longer (cf. A. curta) and by the faet that the posterior
part of the shell is somewhat lower. The wreath of hair round the posterior part of the shell
is sometimes rather sparse; it consists of very fine hairs.
First antenna: —
Female: — This is very powerful and rather short and has its joints very mueh
flattened from the sides. It has six or seven joints, according to whether the third and fourth
joints are free or are united to each other; but even when these two joints are obviously free,
they seem to have only a rather slight power of moving mutually; traces of the original boundary
between them can always be discerned. The first and second joints are subequal and are each
about as long as the total length of all the other joints. The third and fourth joints differ very
mueh in shape from the other joints, as they are more or less triangulär; the posterior edge of
the third joint and the anterior edge of the fourth joint are very mueh shortened. The shape
and the relative length of these two joints afford rather good characters for the species. The
two next distal joints are always well developed and rather large; the end joint is small. All
the species investigated by me appeared to have almost the same equipment of bristles. The
second joint has on the anterior edge near the distal boundary a single rather powerful bristle,
usually pointing forward and hent somewhat upwards, about as long as or rather slightly longer
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