92
THE BIOLOGY O F EUPHAUSIIDS
Nematobrachion sexspinosum Hansen, 191 1
N . sexspinosus Hansen, 1911 : 51 ; 1912: 272-273, pl. x, fig. 6a, pl. xi, fig. 1,
a-i ; Tattersall, 1927 : 24 ; Boden et al., 1955 : 376-377, fig. 46.
This mesopelagic species is rare, Leavitt and Tattersall recording it
from the western Atlantic between 28"N and 29"N and Hansen from
the eastern Atlantic at 32"N ; all other records of this species are from
the Pacific (Fig. 31) except that Baker (personal communication)
considers that he has three juveniles from the transect of 90"E between
the equator and 37"s. The Pacific records are in the west between 30"N
and 30"s ; it appears to be absent from eastern coastal areas and from
the eastern central area of the ocean. The present data suggest that it
lives in regions with temperatures higher than 17OC a t 200 m depth.
Length: males up to about 21 mm, females to about 25 mm. (Hansen,
1911 ; Tattersall, 1927; Leavitt, 1935, 1938; Brinton, 1962a; Ponomareva, 1963.)
Nematobrachion boopis (Calman, 1905)
Nematobrachion boopis Calman,
1905: 153-154, pl. x x v i ; Hansen, 1912: 267-269, pl. x, fig. 5, a-m; Boden el at.,
This mesopelagic species occurs in the Atlantic, Pacific and Indian
Oceans (Fig. 31). Atlantic: recorded off the American coast between
30"N and 40"N and around southern Iceland and northern Scotland
but more common between about 40"N and 40"s ; seems to be absent
from regions off South America. Pacific : found south of about 40"N and
has been captured as far south as 54'22's 177'17'w; appears to be
absent from the Eastern Equatorial Basin. Indian : present between
about 10"N and 35"s.
Length
19-21 mm. (Calman, 1896; Holt and Beaumont, 1902; Hansen, 1905a,
1908a, 1916; Tattersall, 1911, 1912a, 1925, 1927, 1939; Illig, 1930;
Stephensen, 1933 ; Ruud, 1936 ; Leavitt, 1938 ; Einarsson, 1945 ; Boden,
1954, 1961a; Lewis, 1954; Ostvedt, 1955; Fraser, 1956, 1961, 1964;
Brinton, 1962a; Ponomareva, 1963, 1964; Roger, 1967b.)
Nematodactylus boopis Calman, 1896 : 17.
1955 : 377-379, fig. 47.
Lives below 500m during the day.
Genus Stylocheiron G. 0. Sars, 1883b : 29; 1885: 136-137
Stylocheiron carinatum G. 0. Sam, 1883
S. carinaturn G. 0. Sars, 188313: 31; 1885: 137-142, pl. x x v i ; Hansen, 1910:
113-115, pl. xvi, fig. 1, a-h; 1912: 274-276, pl. xi, fig. 2, a-b; Boden et al., 1955:
This species occurs in the Atlantic, Pacific and Indian Oceans
Atlantic: present between about 40"N and 40"s but not
380-381, fig. 48.
(Fig. 32).
THE BIOLOGY O F EUPHAUSIIDS
Nematobrachion sexspinosum Hansen, 191 1
N . sexspinosus Hansen, 1911 : 51 ; 1912: 272-273, pl. x, fig. 6a, pl. xi, fig. 1,
a-i ; Tattersall, 1927 : 24 ; Boden et al., 1955 : 376-377, fig. 46.
This mesopelagic species is rare, Leavitt and Tattersall recording it
from the western Atlantic between 28"N and 29"N and Hansen from
the eastern Atlantic at 32"N ; all other records of this species are from
the Pacific (Fig. 31) except that Baker (personal communication)
considers that he has three juveniles from the transect of 90"E between
the equator and 37"s. The Pacific records are in the west between 30"N
and 30"s ; it appears to be absent from eastern coastal areas and from
the eastern central area of the ocean. The present data suggest that it
lives in regions with temperatures higher than 17OC a t 200 m depth.
Length: males up to about 21 mm, females to about 25 mm. (Hansen,
1911 ; Tattersall, 1927; Leavitt, 1935, 1938; Brinton, 1962a; Ponomareva, 1963.)
Nematobrachion boopis (Calman, 1905)
Nematobrachion boopis Calman,
1905: 153-154, pl. x x v i ; Hansen, 1912: 267-269, pl. x, fig. 5, a-m; Boden el at.,
This mesopelagic species occurs in the Atlantic, Pacific and Indian
Oceans (Fig. 31). Atlantic: recorded off the American coast between
30"N and 40"N and around southern Iceland and northern Scotland
but more common between about 40"N and 40"s ; seems to be absent
from regions off South America. Pacific : found south of about 40"N and
has been captured as far south as 54'22's 177'17'w; appears to be
absent from the Eastern Equatorial Basin. Indian : present between
about 10"N and 35"s.
Length
19-21 mm. (Calman, 1896; Holt and Beaumont, 1902; Hansen, 1905a,
1908a, 1916; Tattersall, 1911, 1912a, 1925, 1927, 1939; Illig, 1930;
Stephensen, 1933 ; Ruud, 1936 ; Leavitt, 1938 ; Einarsson, 1945 ; Boden,
1954, 1961a; Lewis, 1954; Ostvedt, 1955; Fraser, 1956, 1961, 1964;
Brinton, 1962a; Ponomareva, 1963, 1964; Roger, 1967b.)
Nematodactylus boopis Calman, 1896 : 17.
1955 : 377-379, fig. 47.
Lives below 500m during the day.
Genus Stylocheiron G. 0. Sars, 1883b : 29; 1885: 136-137
Stylocheiron carinatum G. 0. Sam, 1883
S. carinaturn G. 0. Sars, 188313: 31; 1885: 137-142, pl. x x v i ; Hansen, 1910:
113-115, pl. xvi, fig. 1, a-h; 1912: 274-276, pl. xi, fig. 2, a-b; Boden et al., 1955:
This species occurs in the Atlantic, Pacific and Indian Oceans
Atlantic: present between about 40"N and 40"s but not
380-381, fig. 48.
(Fig. 32).