Halen (Fig. 7, 8) er meget liden og rudimenter, 
ikke omboiet, og kan heller ikke i Regelen strekkes 
synderlig langt ud fra Skallen. Den ender i 2 skraat 
nedadrettede og jevnsides liggende Flige af triangu- 
ler Form og tet cilierede i Kanterne, hver berende 
i Spidsen en liden, som det synes, fuldsteendig ube- 
vegelig Torn, der aabenbart svarer til Haleklorne 
hos andre bivalve Phyllopoder. Dorsalt findes om- 
trent paa Midten af Halen et stumpt Fremspring, 
hvyortil de 2 Haleborster er festede. Disse er vel 
udviklede, tydeligt 2leddede og tet cilierede. Ha- 
lens ventrale Side er delvis dekket af en eiendom- 
melig, operkelformig Plade (op), der udgaar fra dens 
Basis, og hvortil intet tilsvarende kjendes hos andre 
Phyllopoder. 
De sammensatte Oine (Fig. 11, 0) er beliggende 
ner Forkanten af Hovedet, omtrent ved Enden af 
den iste Trediedel af dets Lengde. De er forholds- 
vis smaa og stoder umiddelbart sammen i Midten, 
saa at de egentlig tilsammen danner et enkelt 
Organ, paa hvilket dog de 2 oprindelige Halvdele 
let lader sig paavise, naar Organet sees forfra (Tab. 
XVIII, Fig. 4) eller nedenfra (Tab. XIX, Fig. 13, 0). 
De er omgivne af en felles Kapsel og viser et stort 
Antal af smaa Krystalkegler udstraalende til alle 
Sider fra det morke Pigment. Som hos Limnadia, 
er de til en vis Grad bevegelige ved Hjelp af 3 fra 
Hovedets Integument til hver Halvdel udgaaende 
Muskler (se Fig. 11). 
I ganske kort Afstand nedenfor de sammensatte 
Mine ligger det enkle Mie (Fig. 11, 13, 14, oc, Fig. 15). 
Det er af en noget uregelmessig afrundet eller ret- 
tere kubisk Form og viser ved noiere Undersogelse, 
-ligesom hos Limnadia, 4 Flader indrammede af et 
morkt Pigment. Fladerne er temmelig sterkt ud- 
buede og viser under visse Belysninger en lignende 
iriserende Glands som hos hin Slegt. Det er holdt 
i Situs ved fine til Hovedets Integument gaaende 
Ligamenter,:hvoraf et fester sig til Forkanten af 
Hovedet ved Basis af Rostrum (Fig. 11, p). 
Umiddelbart foran det enkle Gie bemerkes i 
Hovedets Integument 2 jevnsides stillede aflangt 
ovale Felter (Fig. 11, ol), der er meget skarpt con- 
turerede og har til Underlag en blod Masse af til- 
syneladende ganglios Natur. Ethvert af disse Feld- 
ter (se Fig. 12) er dekket af en’ meget delicat Mem- 
bran, hvorfra et Antal af fine Haar eller Cilier 
springer frem, hvert udgaaende fra en liden knop- 
formig Fortykkelse i Membranen. Der kan neppe 
vere nogen Tvivl om, at disse eiendommelige Dan- 
nelser, der ogsaa er omtalte af Grube, repreesenterer 
et Slags Sandseredskaber, men af hvilken Art er 
vanskeligt at sige. Endnu en eiendommelig Dan- 
nelse maa her omtales. Folger man Dorsalkanten 
16—G. 0. Sars Fauna Norvegiz. 
121 
The tail (figs. 7 and 8) is very small and rudi- 
mentary, is not bent down, and cannot as a rule be 
extended very far from the shell. It ends in 2 obli- 
quely-pointing, juxtaposed lobes of a triangular 
shape, and thickly ciliated at the edges, each car- 
rying at the point a small, apparently quite immov- 
able spine, which evidently answers to the caudal 
claws in other bi-valved Phyllopoda. At about the 
middle of the tail dorsally there is a blunt projec: 
tion, to which the 2 caudal sete are attached. The 
latter are well-developed, distinctly 2-jointed and 
thickly ciliated. The ventral surface of the tail is 
partly covered by a peculiar opercular lamella (op), 
issuing from its base, and to which there is nothing 
corresponding in other Phyllopoda. 
The compound eyes (fig. 11,0) are situated near 
the front margin of the head, at about the end of 
the first third of its length. They are compara- 
tively small, and meet in the middle, thus forming 
in reality a single organ, in which, however, the 
2 original halves may be easily distinguished, when 
the organ is seen from the front (Pl. XVII, fig. 4) 
or from below (Pl. XIX, fig. 13, 0). They are sur- 
rounded by a common capsule, and exhibit a large 
number of small crystalline cones radiating to all 
sides from the dark pigment. As in Limnadia, they 
are movable to a certain extent by the help of 3 
muscles issuing from the integument of the head to 
each half (see fig. 11). 
At a very short distance below the compound 
eyes, is the ocellus (figs. 11, 13, 14 oe, fig. 15). It 
is of a somewhat irregular, rounded or rather cubi- 
cal shape, and presents, on a closer examination, 
just as in Limnadia, 4 surfaces encircled by a dark 
pigment. The surfaces are not a little convex, and 
in certain lights, like the above-mentioned genus, 
have an iridescent lustre. It is held in position by 
fine ligaments running to the integument of the 
head, one of which is fastened to the anterior 
margin of the head at the base of the rostrum (fig. 
11, p). 
Immediately in front of the ocellus, may 
be observed, in the integument of the head, 2 
juxtaposed oblong oval fields (fig. 11, ol) very 
sharply outlined, and with a soft mass of an ap- 
parently ganglionic nature as sub-stratum. Each 
of these fields (see fig. 12) is covered by a very 
delicate membrane, from which spring a number 
of fine hairs or cilia, each issuing from a little 
nodiform thickening of the membrane. There 
can hardly be any doubt that these peculiar for- 
mations, which are also mentioned by Grube, re- 
present a kind of sensory apparatus, but of what 
kind, it is difficult to say. Yet another peculiar 
formation must be mentioned here. In following 
