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13. Sphyrapus serratus. Gr. O. Sars, n. sp.
(PI. XXI).
1 Sphyrapus serratus. (i. O. Sars. Revision ai’ Gruppen Isopoda ehelifera,
PS. 20.
Artseharacteristik. Legemet hos Hunnen neppe 5
Gange saa langt som bredt, bos Hannen betydelig smækrere.
Pandepladen meget bred, horizontal, i Midten uddraget i
en stump 4-tandet Spids. Sidste Forkropssegment betydelig
kortere end de øvrige. Bagkroppens 5 første Segmenter
med udstaaende, triangulært tilspidsede Epimerer. Sidste
Segment stumpt tilrundet. Ingen Øine. 1ste Par Foleres
Basalled meget stort, udvidet paa Midten, med 4 Borster
i den ydre Kant; den indre Svøbe ganske kort, 3-leddet,
den vdre hos Hunnen 5-leddet. hos Hannen 7-leddet.
Sax-lVidderne kraftigt udviklede, med stærkt opsvulmet Haand,
Tibialleddet hos Hannen længere end Tarsalleddet.
Graveføddernes næstsidste Led hos Hunnen bevæbnet med 3
stærke Torner i den indre Kant. Halevedhængene neppe
længere end Bagkroppen, med den ydre Gren meget liden
og 3-leddet, den indre 10-leddet. Farven ensformig hvid.
Længden 5—6""".
Findesteder. Ståt. 40, 51, 353.
Bemærkninger. Nærværende Art viser en saa
paafaldende Lighed med den af mig tidligere characteriserede
norske Art. Sph. ammalm. at jeg i lang Tid kun holdt
den for en Varietet af samme. Ved den nøiere anatomiske
Undersøgelse, jeg senere har anstillet over begge disse
Former, har jeg dog fundet visse constante Forskjelligheder
saavel hos Hun som hos Han. der gjør det nødvendigt at
skille dem som distincte Arter. Et meget let opfatteligt
ydre Kjendeiuærke for nærværende Art er de til Siderne
stærkt udstaaende og triangulært tilspidsede Epimerer paa
Bagkroppens 5 første Segmenter, hvilket har givet
Anledning til Artsbenævnelsen. Hos Sph. anomalus er disse
Segmenter til Siderne stumpt afrundede, og hele Bagkroppen
synes derved ogsaa her betydelig smalere.
Beskrivelse af Hunnen. Legemet er (se Pl. XXI,
Fig. 1 og 2) noget nedtrykt og jevnt afsmalnende bagtil,
med den største Brede, der falder over 1ste frie
Forkropssegment, noget større end ’/:, af Længden.
Integuiuenterne er temmelig haarde, glatte og
glind-sende, samt uden nogen bemærkelig Haarbesætning, naar
afsees fra Lemmerne.
Det forreste Kropssegfnent. der kun uegentlig kan
benævnes Hovedet, da det i sig tillige indbefatter det 1ste
fodbærende Segment, er meget stort, dannende et Slags
Rygskjold (carapax) af triangulær Form, med den største
Brede, der omtrent er lig Længden, i sin bagerste Del.
Fortil gaar det ud i en bred, horizontal Pandeplade, der i
Enden er udtrukket i en kort stump Spids besat med 4
smaa Tænder (se Fig. 4). Ved Basis af denne Pandeplade
og indtagende Sidehjornerne af Hovedskjoldet sees 2 smaa
13. Sphyrapus serratus. G. O. Sars, n. sp.
I Pl. XXI).
Sphyrapus serratus, G. O. Sars. Revision af Gruppen Isopoda ehelifera.
p. -20.
Specific Character. — Body in female scarcely 5
times as long as broad, in male much more slender.
Frontal plate exceedingly broad, horizontal, produced in
the middle to an obtuse four-toothed point. Last thoracic
segment considerably shorter than the others. Five first
segments of abdomen with projecting, triangular, acuminate
epimera. Last segment obtusely rounded. No eyes. Basal
joint of 1st pair of antenna* exceedingly large, dilated in
the middle, with 4 bristles on the outer margin: inner
Hagellum very short, three-jointed: outer in female
five-jointed, in male seven-jointed. Chelipeds powerfully
developed, with the hand greatly swollen: tibial joint in male
longer than tarsal joint. Penultimate joint of fossorial legs
in female armed with 3 strong spines on the inner margin.
Caudal appendages scarcely, if at all. longer than posterior
division of body, with the outer branch exceedingly small
and three-jointed, the inner ten-jointed. Colour a uniform
white. Length from 5 to 6""".
Locality. — Stats. 40, 51. 353.
Remarks. — The present species exhibits so striking
a resemblance to the Norwegian I had previously described
under the name of Sph. anomalus, that I long held it
to be a mere variety of that form. Meanwhile, a closer
anatomical examination of both these animals has brought
to light divers constant deviations both in the female and
the male, that render it necessary to establish them as
distinct species. A readily appreciable outer characteristic
in the present form are the triangularly pointed epimera
on the 5 first segments of the abdomen, prominently
projecting toward either side, from which indeed the specific
designation is derived. In Sph. anomahts, these segments
are at the sides obtusely rounded: and hence the whole
posterior division of the body in that species too. appears
considerably more slender than in the present form.
Description of the Female. — The body somewhat
depressed (see Pl. XXI. tigs. 1. 2) and tapering gradually
backward, with its greatest breadth, that occurs across the
1 st free thoracic segment, slightly exceeding one-fifth of the
length.
The integuments comparatively hard, smooth, and
lustrous, as also without any covering of hair, except on
the appendages.
The most anterior segment of the body, which in
anything but a strict sense can be termed the head,
comprising as it does also the 1st pedigerous segment, is
exceedingly large, constituting a kind of carapax. triangular
in form, its greatest breadth about equal to the length across
the posterior portion. Anteriorly, it projects as a broad,
horizontally extending frontal plate, which, at the extremity,
is produced to a short, obtuse point, beset with 4 small
teeth (see fig. 4). At the base of this frontal plate, and
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