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246
Cryptoniseid
(PI. C, fig. 3).
No. 2.
Characters. Body, as seen from above, oblong fusiform in outline, broadest
in the middle, and tapering to almost an equal extent both anteriorly and posteri-
orly. Cephalic segment considerably narrowed in front, with the extremity narrowly
rounded ; anal segment forming behind a rounded lamellar expansion
divided into
7 coarse teeth. Eyes inconspicuous. Basal joint of antennulae forming behind a
very large laminar expansion divided into 9 closely crowded acute teeth; the 2
succeeding joints densely
covered in front with small denticles. Antennae com-
paratively short, scarcely extending beyond the 2nd pedigerous segment, flagellum
much shorter than the peduncle. Coxal plates distinctly pectinate. Legs of nor-
mal structure, the posterior pairs rather slender, with the dactylus simple. Uro-
poda somewhat resembling in structure those in the corresponding stage
of the
DajidcB, the rami being linear in form and terminating in several denticles, outer
ramus, however, considerably shorter than the inner. Length of body 0.90 mm.
Found attached beneath the anal segment of ^Ega ventrosa M. Sars.
Remarks. This form somewhat resembles in its outward appearance some
of the Dajid larvae figured by Dr. Hansen in his account of the Isopoda of the
German Plankton Expedition, and the structure of the uropoda likewise approaches
that found in the larvae belonging to that family; but the structure of the
antennulse is essentially different, and agrees with that in the Cryptoniseid larvae,
and the oral cone lacks all trace of the sucking disc so characteristic of the
Dajid
larvae. On account of these 2 latter characters and also of the structure of
the legs, this form ought certainly to be referred to the family Cryptoniscidoe ;
but at present it is impossible to recognise its relationship to the several genera
comprised within that family.
Occurrence. All the specimens examined by me were taken from the
same species of ^Ega, viz., ^E. ventrosa M. Sars, and were invariably found
firmly attached to the lower face of the anal segment or telson, near the anal
opening, sometimes but a single specimen, sometimes 2 such in each ^Ega. ^_The
latter were collected by the aid of the dredge from a depth
off the Nordland coast.
of 60 100 fathoms