328
THE BIOLOGY OF EUPHAUSIIDS
atZantica (?); NematobracAion flexipes, 3. booj~is; StyZocAeiron carinaturn,
S. aflne, 8. szchmii, S. microphthlma, S. elongatum, S. Zongicorne, S.
abbreviatum, 8. maximum.
(b) Species confined to the Pacific and Atlantic Oceans.
Nyctiphanes simplex; Euphausia eximia; ThysanoZssa inermis,
(c) Species confined to the Pacific and Indian Oceans.
Pseudeuphausia latifrons; Euphausia diomedeae, E. distinguenda,
E. paragibba; Nematoscelis gracilis.
(d) Species confined t o the Atlantic and Indian Oceans.
Thysanopoda microphthalma.
(e) Species confined to the Atlantic Ocean.
Meganyctiphanes norvegica; Nyctiphanes couchii, N . capensis;
Euphausia americana, E . Icrohnii, E . hanseni; Thysanoessa longicaudata.
(f) Species confined to the Pacific Ocean.
Nyctiphanes australis; Pseudeuphausia sinica; Euphausia pacijka,
E . nana, E . mucronata, E . sibogae, E . lamelligera, E . gibba, E . fallax;
Tessarabrachion ocubtum; Thysanoessa spinifera, T . longipes, T .
inspinata; Nematoscelis diflcilis, N . lobata; Stylocheiron insulare, S.
robustum.
T . raschii; Nematobrachion sexspinosum.
(g) Species confined to the Indian Ocean.
Stylocheiron indicum.
(h) Species confined to the Indian Ocean and Red Sea.
Euphausia sanzoi.
Among the widely distributed species are those which have circumpolar distributions in the Antarctic, namely Euphausia vallentini,
E. superba, E. lucens, E. frigida, E. crystallorophias, E. similis, E. similis
var. armata, Thysanoessa macrura, T . vicina. Two species, Thysanopoda
acutifrons and Thysanoessa gregaria, have bipolar or bi-antitropical
distributions, that is occur in a northern and a southern latitudinal area.
Nematoscelis megalops has northern and southern areas of occurrence
in the Atlantic but only occurs in southern regions of the Pacific and
Indian Oceans, the comparable northern latitudinal range in the
Pacific being occupied by the closely related species, N . dificilis which
is confined to the North Pacific. Thysanopoda obtusifrons, Euphausia
rnutica, E . brevis, E . recurua, Thysanoessa parva, and Nematoscelis
atlantica have bi-antitropical distributions in the Pacific, being restricted
to the warmer regions at depths of 400 m ; the temperatures throughout
the regions 40"N-40°S are higher on average in the Atlantic than in the
Pacific (Fig. 119) and present evidence suggests that most of these
species probably have a continuous distribution throughout their
latitudinal range in the Atlantic.
THE BIOLOGY OF EUPHAUSIIDS
atZantica (?); NematobracAion flexipes, 3. booj~is; StyZocAeiron carinaturn,
S. aflne, 8. szchmii, S. microphthlma, S. elongatum, S. Zongicorne, S.
abbreviatum, 8. maximum.
(b) Species confined to the Pacific and Atlantic Oceans.
Nyctiphanes simplex; Euphausia eximia; ThysanoZssa inermis,
(c) Species confined to the Pacific and Indian Oceans.
Pseudeuphausia latifrons; Euphausia diomedeae, E. distinguenda,
E. paragibba; Nematoscelis gracilis.
(d) Species confined t o the Atlantic and Indian Oceans.
Thysanopoda microphthalma.
(e) Species confined to the Atlantic Ocean.
Meganyctiphanes norvegica; Nyctiphanes couchii, N . capensis;
Euphausia americana, E . Icrohnii, E . hanseni; Thysanoessa longicaudata.
(f) Species confined to the Pacific Ocean.
Nyctiphanes australis; Pseudeuphausia sinica; Euphausia pacijka,
E . nana, E . mucronata, E . sibogae, E . lamelligera, E . gibba, E . fallax;
Tessarabrachion ocubtum; Thysanoessa spinifera, T . longipes, T .
inspinata; Nematoscelis diflcilis, N . lobata; Stylocheiron insulare, S.
robustum.
T . raschii; Nematobrachion sexspinosum.
(g) Species confined to the Indian Ocean.
Stylocheiron indicum.
(h) Species confined to the Indian Ocean and Red Sea.
Euphausia sanzoi.
Among the widely distributed species are those which have circumpolar distributions in the Antarctic, namely Euphausia vallentini,
E. superba, E. lucens, E. frigida, E. crystallorophias, E. similis, E. similis
var. armata, Thysanoessa macrura, T . vicina. Two species, Thysanopoda
acutifrons and Thysanoessa gregaria, have bipolar or bi-antitropical
distributions, that is occur in a northern and a southern latitudinal area.
Nematoscelis megalops has northern and southern areas of occurrence
in the Atlantic but only occurs in southern regions of the Pacific and
Indian Oceans, the comparable northern latitudinal range in the
Pacific being occupied by the closely related species, N . dificilis which
is confined to the North Pacific. Thysanopoda obtusifrons, Euphausia
rnutica, E . brevis, E . recurua, Thysanoessa parva, and Nematoscelis
atlantica have bi-antitropical distributions in the Pacific, being restricted
to the warmer regions at depths of 400 m ; the temperatures throughout
the regions 40"N-40°S are higher on average in the Atlantic than in the
Pacific (Fig. 119) and present evidence suggests that most of these
species probably have a continuous distribution throughout their
latitudinal range in the Atlantic.