THE BREEDING OF THE NORTH ATLANTIC FRESHWATER-EELS
165
with the larger leptocephalus, which he could follow through metamorphosis stages to a t least adolescent specimens ; the type specimen,
caught mesopelagically, is 249 mm in length.
For our discussion the important point about this species is that,
although breeding in the same area in the North Atlantic as the
geminate species of Anguilla, Conger, Synaphobranchus, and Leptocephclus similis-euryurus, there is one and only one species in the
North Atlantic; its number of myomeres being 150-160.
In fact, one could also speak about geminate species in Nesaorhamphus, but here the breeding places arc totally separated, the other
species in the Atlantic Nessorhamphus danae Johs. Schmidt breeding
around the Equator and having 135-145 myomeres. And then again
a single leptocephalus found in the South Atlantic indicates a subtropical
population of N . ingoljianus corresponding to the North Atlantic
(Schmidt et at., 1932, p. 252). Finally we may refer to the worldwide, but sporadic occurrence in all oceans; it is equally important to
note the slight variation in number of myomeres from one population
to another within the same species, and that the occurrences, except
for the Equatorial and South Atlantic, coincide with areas where
leptocephali of Anguilla species also occur.
The other apodal fish to be mentioned here is Serrivomer beani
Gill and Ryder 1883, also of a meso- or bathypelagic occurrence, while
its leptocephalus is epipelagic.
Schmidt (1930, p. 374) mentions its leptocephalus, L. lanceolatus
Strbmman, as one of several other Muraenoids spawning in the Sargasso
Sea, but in this case spawning takes place in autumn and winter.
Bauchot (1959) has given a very detailed account of the whole material,
5624 specimens, from which it is quite clear that there i
R only one
breeding population; the number of myomeres is 156 to 163.
It is also possible, however, here to speak about geminate species,
the other species being Serrivomer brevidentatus Roule and Bertin
1929, and its leptocephalus L . lanceolatoides Johs. Schmidt 1916 with
the number of myomeres of 155 to 165. Thus the number of myomeres
are essentially the same in L. lanceolatus and L. lanceolatoides, but
several other characters make it easy to distinguish between the two
(Schmidt, 1916 ; Bauchot, l959), and the smallest leptocephali were
caught between April and August. Bauchot studied a total of 1653
specimens of this species. Figures 42 and 43, in Bauchot (1959), show
clearly that L. lanceolatoides spawns farther north than L. lanceolatwr.
But none of them show the slightest sign of splitting up into ecophenotypes.
This seems in good agreement with the fact that the adults live meso-
165
with the larger leptocephalus, which he could follow through metamorphosis stages to a t least adolescent specimens ; the type specimen,
caught mesopelagically, is 249 mm in length.
For our discussion the important point about this species is that,
although breeding in the same area in the North Atlantic as the
geminate species of Anguilla, Conger, Synaphobranchus, and Leptocephclus similis-euryurus, there is one and only one species in the
North Atlantic; its number of myomeres being 150-160.
In fact, one could also speak about geminate species in Nesaorhamphus, but here the breeding places arc totally separated, the other
species in the Atlantic Nessorhamphus danae Johs. Schmidt breeding
around the Equator and having 135-145 myomeres. And then again
a single leptocephalus found in the South Atlantic indicates a subtropical
population of N . ingoljianus corresponding to the North Atlantic
(Schmidt et at., 1932, p. 252). Finally we may refer to the worldwide, but sporadic occurrence in all oceans; it is equally important to
note the slight variation in number of myomeres from one population
to another within the same species, and that the occurrences, except
for the Equatorial and South Atlantic, coincide with areas where
leptocephali of Anguilla species also occur.
The other apodal fish to be mentioned here is Serrivomer beani
Gill and Ryder 1883, also of a meso- or bathypelagic occurrence, while
its leptocephalus is epipelagic.
Schmidt (1930, p. 374) mentions its leptocephalus, L. lanceolatus
Strbmman, as one of several other Muraenoids spawning in the Sargasso
Sea, but in this case spawning takes place in autumn and winter.
Bauchot (1959) has given a very detailed account of the whole material,
5624 specimens, from which it is quite clear that there i
R only one
breeding population; the number of myomeres is 156 to 163.
It is also possible, however, here to speak about geminate species,
the other species being Serrivomer brevidentatus Roule and Bertin
1929, and its leptocephalus L . lanceolatoides Johs. Schmidt 1916 with
the number of myomeres of 155 to 165. Thus the number of myomeres
are essentially the same in L. lanceolatus and L. lanceolatoides, but
several other characters make it easy to distinguish between the two
(Schmidt, 1916 ; Bauchot, l959), and the smallest leptocephali were
caught between April and August. Bauchot studied a total of 1653
specimens of this species. Figures 42 and 43, in Bauchot (1959), show
clearly that L. lanceolatoides spawns farther north than L. lanceolatwr.
But none of them show the slightest sign of splitting up into ecophenotypes.
This seems in good agreement with the fact that the adults live meso-