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joint nearly twice as long as the other 2 combined, in male considerably
more elongated, and composed of 5 articulations successively diminishing in size,
the outer 2 representing the flagellum. Chelipeds in female of moderate size,
hand oval, with the ringers comparatively short, the thumb having, inside, 3 serra-
tions, the dactylus a single tubercle; those in male of enormous size, carpus very
large and produced in front, outside the hand, to a lamellar lobe, hand imper-
fectly chelate, the thumb being transformed into a thin, reflexed lappet instricted
at the base, dactylus long and falciform, with 3 small denticles inside. First
pair of pereiopoda much larger than the others, the 3 posterior pairs more
strongly built than the 2 preceding ones, with the basal joint rather tumid. Uro-
poda about half the length of the nietasome, inner ramus 4-articulate, outer very
small and biarticulate. Colour whitish. Length of adult female 2 mm.,
about the same.
of male
Remarks. The very pronounced sexual difference occurring in the present
form has caused it to be twice described under 2 different names. Kroyer de-
scribed the female as Tanais Orstedi and the male as T. curculio, and some years
afterwards Fr. Mliller, having apparently not been aware of Kroyer's description,
recorded the same form under 2 different names, viz. : Tanais balthicus (the female)
and T. rhynchites (the male). In this manner therefore, no less than 4 different
names have been assigned to the same species. As Kroyer was the first to
observe the species, one of his 2 specific names ought to be retained for the
species, and more properly that by which the female was described. From the
Mediterranean species, H. anomalus, the present form is easily distinguished by
the very different aspect of the male.
Occurrence. I have taken this form rather plentifully in the Iddefjord at
Fredrikshald, wh^re it occurred on a muddy bottom at a depth
of 3 6 fathoms.
Male specimens were, as usual, far less frequent than female ones, of which
numerous specimens, both young and adult, were collected. Some specimens
of this form are moreover contained in our University Museum, having been
taken by the late Dr. Boeck from piles of the quay
at Christiansand.
Distribution. Oresund (Kroyer), Baltic at Landskrona and Westervik
(Lilljeb.), Prussia at Greifswalde (Fr. Milller), Bohuslan (Lilljeb.).