166
ANTON F. BRIiUN
Schmidt’s larvae, which were preserved in formalin. The ‘‘ Arcturus ”
did not catch A . rostrata leptocephali until July, and ther only two
specimens, 39-43 mm, which is exactly what would be expected from a
glance at the catch of Dana station 891 fairly near t o Bermuda IS.
(Schmidt, 1925, Fig. 14). That Tucker (1959a, p. 500) should consider
a find of eggs so far north and lacking a concentrated oil-globule as
explained by the assumption that they merely represented one of the
many mistimed and misplaced spawnings, seems utterly improbable
t o me. The more so because the ‘‘ Arcturus ” also caught seven
A . anguilh leptocephali in July, which also fitted into Schmidt’s picture, but none was smaller t,han 18 mm, and this was a single specimen,
while the rest were larger than 28 mm.
Incidentally I (Bruun, 1937, p. 9) have pointed out that Uchida
(1 935) also misidentified a leptocephalus close to Leptocephalm similis
as the larva of A . japonica. Uchida overlooked the possibility that
another genus of apodal fish might have the same number of myomeres
as the Anguilla, as is the case with Lept. similis and L. euryurus in the
North Atlantic; Uchida’s larva may thus be a Pacific parallel to
A. japonica, as are L. similis to A . rostrata and L. euryurus to A .
anguilla.
VIII. POSSIBLE TEMPERATURE EFFECTS ON THE NUMBER OF
VERTEBRAE IN Anguilla
Out of the sixteen species of the genus Anguilla examined by Ege
(1939) A . mossambica has the lowest number of vertebrae, namely an
average of 102.9, varying between 100 and 106. The highest number is
found in A . japonica, with an average of 115.8 and a variation between
112 and 119. This makes a total variation of 100 to 119 within the
genus.
From Table 111 i t may be seen that A . japonica and A . anguilla
represent the extreme high numbers, while A . rostrata in some way
may be said t o show a number rather close to the average number of
the rest of the species.
Furthermore it may be noted that only in A . bicolor the subspecific
difference may be about 2.
I do not want to discuss in detail whether one may be justified in
expecting that the variation of the number of vertebrae should be
directly proportional to the total number of vertebrae, when comparing species of higher taxons than a genus. Tucker (1959a, p. 498)
supposes this when comparing Salmo trutta (order Isospondyli) with
Anguilla anguilla and A . rostrata (order Apodes). I would just mention
ANTON F. BRIiUN
Schmidt’s larvae, which were preserved in formalin. The ‘‘ Arcturus ”
did not catch A . rostrata leptocephali until July, and ther only two
specimens, 39-43 mm, which is exactly what would be expected from a
glance at the catch of Dana station 891 fairly near t o Bermuda IS.
(Schmidt, 1925, Fig. 14). That Tucker (1959a, p. 500) should consider
a find of eggs so far north and lacking a concentrated oil-globule as
explained by the assumption that they merely represented one of the
many mistimed and misplaced spawnings, seems utterly improbable
t o me. The more so because the ‘‘ Arcturus ” also caught seven
A . anguilh leptocephali in July, which also fitted into Schmidt’s picture, but none was smaller t,han 18 mm, and this was a single specimen,
while the rest were larger than 28 mm.
Incidentally I (Bruun, 1937, p. 9) have pointed out that Uchida
(1 935) also misidentified a leptocephalus close to Leptocephalm similis
as the larva of A . japonica. Uchida overlooked the possibility that
another genus of apodal fish might have the same number of myomeres
as the Anguilla, as is the case with Lept. similis and L. euryurus in the
North Atlantic; Uchida’s larva may thus be a Pacific parallel to
A. japonica, as are L. similis to A . rostrata and L. euryurus to A .
anguilla.
VIII. POSSIBLE TEMPERATURE EFFECTS ON THE NUMBER OF
VERTEBRAE IN Anguilla
Out of the sixteen species of the genus Anguilla examined by Ege
(1939) A . mossambica has the lowest number of vertebrae, namely an
average of 102.9, varying between 100 and 106. The highest number is
found in A . japonica, with an average of 115.8 and a variation between
112 and 119. This makes a total variation of 100 to 119 within the
genus.
From Table 111 i t may be seen that A . japonica and A . anguilla
represent the extreme high numbers, while A . rostrata in some way
may be said t o show a number rather close to the average number of
the rest of the species.
Furthermore it may be noted that only in A . bicolor the subspecific
difference may be about 2.
I do not want to discuss in detail whether one may be justified in
expecting that the variation of the number of vertebrae should be
directly proportional to the total number of vertebrae, when comparing species of higher taxons than a genus. Tucker (1959a, p. 498)
supposes this when comparing Salmo trutta (order Isospondyli) with
Anguilla anguilla and A . rostrata (order Apodes). I would just mention