NARRATIVE OF THE CRUISE. 
743 
small Crustacea, especially Isopocla and Amphipoda, and the similarity of these species 
with northern forms is on the whole very striking. A small Cumacean of the genus 
Lexicon seems hardly to be distinguishable from the well known northern species, Leucon 
nasicus of Kroyer.” 
The Pkyllocarida. — “ Of Phyllocarida a new species of Nebalia has been described by 
v. Willemoes Suhm from the Bermudas (see p. 1 50). Another large and very interesting 
deep-sea Phyllocarid, apparently nearly related to Nebalia , w T as met with at two different 
localities. Of one of the specimens only the carapace and a fragment of the anterior 
part of the body have been secured. It seems to be this imperfect specimen that the 
late Dr. v. Willemoes Suhm mentioned in one of his letters to Professor v. Siebold 1 as a 
gigantic Ostracode. Fortunately another more perfect, though smaller, specimen was 
afterwards collected in the South Pacific when the dredge had been down to the 
considerable depth of 2550 fathoms, showing clearly that it is a Phyllocarid, and not, 
as first suggested, an Ostracode. The most striking characters of this form are the 
distinctly sculptured carapace, the rudimentary eyes, and the remarkably feeble structure 
of the branchial legs, distinguishing it from Nebalia as a distinct genus, Nebaliopsis, 
G. 0. Sars.” 
The phosphorescent light emitted by the species of the Euphausiidse was frequently 
under observation during the cruise. If one of these be taken up by a pair of forceps when 
newly caught, a pair of bright phosphorescent spots will be observed directly behind the 
eyes, two other pairs on the trunk, and four other spots situated along the median line 
of the tail. These can all be quite well seen with the naked eye. The pair close to the 
eyes are first and most brilliantly illuminated, and then the light, which is bluish white, 
spreads to the other organs on the trunk and tail. After a brilliant flash has been 
emitted from the organs they glow for some time with a dull light. The light is given 
out at will by the animal, and usually, but not always, when irritated. The most brilliant 
flashes occur when freshly taken from the sea. Subsequent flashes become less and less 
bright, till the animal appears to lose the power of emitting light. If the organs be 
removed with the forceps the points will glow brightly for some time, and when the 
animal is dying the whole body is frequently illuminated by a diffused light. These 
phosphorescent organs appear under the microscope as pale red spots with a central clear 
lenticular body. The phosphorescent light comes from the red pigment surrounding 
the lenticular space. In August 1880 Mr. Murray observed at night on the surface of 
the sea in the Fseroe Channel large patches and long streaks of apparently milky white 
water. The tow-nets caught in these immense numbers of Nyctiphanes ( Thymnopoda ) 
norvegica, M. Sars, and the peculiar appearance of the water seemed to be due to the 
diffused light emitted from the phosphorescent organs of this species. 
1 Brief II., Zeitschr. f. viiss. Zool., Bd. xxiv. p. xiii., 1874. 
(narr. chall. exp. — vol. i. — 1885.) 
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