90
THE BIOLOGY OF EUPHAUSIIDS
Nematoscelis gracilis Hansen, 1910
N . qracilis Hansen, 1910: 109-110, pl. xv, fig. 3, a-g; 1912: 261-263, p1. x,
fig. 2a; Boden et al., 1955: 369-371, fig. 43.
N . gracilis occurs in the Pacific and Indian Oceans but probably
not in the Atlantic although Illig records it a t 2"37'N 3"28'E (Fig. 28).
It is found between 20"N and 20"s in the equatorial Pacific and extends
northward in the Western Pacific in the Kuroshio Current and its
Extension east of Japan. It is present in the Indian Ocean north of
about 10"s although Illig found it near 30"s 85"E. Probably lives
between 300 and 500 m depth during the day, and between 100 m and
300 m depth a t night. Length : males up to 11.5 nim, females up t o
15.5 mm. (Tattersall, 1912a, 1939; Hansen, 1915, 1916; Illig, 1930;
Torelli, 1934; Brinton, 1962a; Ponomareva, 1963, 1964; Roger, 1967b.)
Genus Nematobrachion Calman, 1905 : 153
Nematobrachion Jlexipes (Ortmann, 1893)
StyZocheiron Jlexipes Ortmann, 1893: 18, taf. 1, fig. vii. Nematodactylus
Jlezipes Calman, 1896 : 16. Nematobrachion Jlexipes Calman, 1905 : 153-155 ;
Hansen, 1911 : 51 ; 1912 : 269-272, pl. x, fig. 5, a-m; Banner, 1950: 15-18;
Boden et al., 1955 : 373-376, fig. 45.
This species has been found in the Atlantic, Pacific and Indian
Oceans but very few specimens are usually obtained in any one haul.
Atlantic : present south of 40"N off the American and European coasts
and off northeastern South America and West Africa to about 40"s but
the records are few and scattered. Pacific : occurs south of about 40°N,
but has been caught in the coastal waters of Alaska and British Columbia
(58"N) and is present in many areas throughout the Pacific to about
30"s to 40"s. Only two areas of " abundance ') have so far been found,
the first in the southern region of the Californian Current off Baja
California, the second just south of the equator extending from the
coastal regions of Peru and Ecuador to about 1 l0"W to 120"W ; Brinton
concluded that these are breeding areas of this species. Indian : found
in the Gulfs of Oman and Aden and in the Arabian Sea and Bay of
Bengal; IIlig has one doubtful record a t 59"16.3'5 40'13.7'E. Lives
between 280 and 700 m during the day, above 280 m at night. Length
up to 22-23mm (Ortmann, 1893; Tattersall, 1912a, 1927, 1939;
Hansen, 1915, 1916; Illig, 1930; Leavitt, 1935, 1938; Ruud, 1936;
Boden, 1954; Nepgen, 1957 ; Brinton, 1962a; Ponomareva, 1963, 1964;
Grindley and Penrith, 1965; Roger, 1967b.)
THE BIOLOGY OF EUPHAUSIIDS
Nematoscelis gracilis Hansen, 1910
N . qracilis Hansen, 1910: 109-110, pl. xv, fig. 3, a-g; 1912: 261-263, p1. x,
fig. 2a; Boden et al., 1955: 369-371, fig. 43.
N . gracilis occurs in the Pacific and Indian Oceans but probably
not in the Atlantic although Illig records it a t 2"37'N 3"28'E (Fig. 28).
It is found between 20"N and 20"s in the equatorial Pacific and extends
northward in the Western Pacific in the Kuroshio Current and its
Extension east of Japan. It is present in the Indian Ocean north of
about 10"s although Illig found it near 30"s 85"E. Probably lives
between 300 and 500 m depth during the day, and between 100 m and
300 m depth a t night. Length : males up to 11.5 nim, females up t o
15.5 mm. (Tattersall, 1912a, 1939; Hansen, 1915, 1916; Illig, 1930;
Torelli, 1934; Brinton, 1962a; Ponomareva, 1963, 1964; Roger, 1967b.)
Genus Nematobrachion Calman, 1905 : 153
Nematobrachion Jlexipes (Ortmann, 1893)
StyZocheiron Jlexipes Ortmann, 1893: 18, taf. 1, fig. vii. Nematodactylus
Jlezipes Calman, 1896 : 16. Nematobrachion Jlexipes Calman, 1905 : 153-155 ;
Hansen, 1911 : 51 ; 1912 : 269-272, pl. x, fig. 5, a-m; Banner, 1950: 15-18;
Boden et al., 1955 : 373-376, fig. 45.
This species has been found in the Atlantic, Pacific and Indian
Oceans but very few specimens are usually obtained in any one haul.
Atlantic : present south of 40"N off the American and European coasts
and off northeastern South America and West Africa to about 40"s but
the records are few and scattered. Pacific : occurs south of about 40°N,
but has been caught in the coastal waters of Alaska and British Columbia
(58"N) and is present in many areas throughout the Pacific to about
30"s to 40"s. Only two areas of " abundance ') have so far been found,
the first in the southern region of the Californian Current off Baja
California, the second just south of the equator extending from the
coastal regions of Peru and Ecuador to about 1 l0"W to 120"W ; Brinton
concluded that these are breeding areas of this species. Indian : found
in the Gulfs of Oman and Aden and in the Arabian Sea and Bay of
Bengal; IIlig has one doubtful record a t 59"16.3'5 40'13.7'E. Lives
between 280 and 700 m during the day, above 280 m at night. Length
up to 22-23mm (Ortmann, 1893; Tattersall, 1912a, 1927, 1939;
Hansen, 1915, 1916; Illig, 1930; Leavitt, 1935, 1938; Ruud, 1936;
Boden, 1954; Nepgen, 1957 ; Brinton, 1962a; Ponomareva, 1963, 1964;
Grindley and Penrith, 1965; Roger, 1967b.)