AUGUST 22, 1912] 
NATURE 
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that at Gibraltar most larve were taken in winter. 
\With an average rapidity of twelve miles in the 
day, the currents will carry the larve from 
Gibraltar to Messina in the course of three months. 
Larvae of the Eel (Lept. brevirostris). Distribution compared 
with Age (from Investigations with the Thor and other 
Danish Vessels). 
Percentage 
of specimens 
smaller than 
jommn. 
Région 
Atlantic S. of ca. 45° N. and W. of ca. 20° W. ... 100 
. Nvofca. 45, N. and BE. of ca. 15)W. ... ca. 5 
Mediterranean W. of 3° W and Straits of Gibraltar ,, 60 
i E. of 3° W. Siow SSS 
Messina (collections between Marchigtt—May1912) ,, 3 
Atlantic eels all belong to the same _ species. 
Further, Cand. Strubberg has counted the vertebra 
in 2000 specimens from the Atlantic and 1000 from 
the Mediterranean, and found as average number 
for the former 114°731, for the latter 114°736, thus 
complete agreement, and there is nothing to 
oppose the view that the Mediterranean eels come 
from the Atlantic. (4) The eel larvae which I have 
taken in the Mediterranean measure 60-85 mm., 
those of Grassi were 60-77 mm. This good agree- 
| ment, based on a large number of specimens taken 
throughout the year, shows that the Mediterranean 
larva are older, almost or quite full-grown speci- 
mens—a condition very different from what we 
find far out in the Atlantic, where 
all the larve obtained are less 
than 60 mm. (see Table and 
Fig. 2). 
This positive evidence that the 
eel larve are carried into the 
Mediterranean from the Atlantic 
may be supplemented by the 
negative. In spite of our excel- 
lent apparatus and numerous 
stations at all times of the year, 
we have never found larve or 
eggs of the eel in the Mediterra- 
nean. Nor have other investiga- 
tors found them; the eggs and 
larvee which Grassi (latest in 1910) 
referred with much doubt to the 
eel belong to other species, as 
I have been able to show in my 
detailed work which has just been 
published. 
Altogether, the result is that the 
stock of eels in the Mediterranean 
comes from the Atlantic. Just as 
from the North Sea, Baltic, and 
northern Norway, the maturing 
eels must migrate out of the Medi- 
terranean—even from its most 
eastern parts—to spawn in the 
Atlantic, and thereafter probably 
die. Wecannot say as yet where 
exactly the spawning takes place, 
and but little more than that the 
spawning places must lie in the 
Atlantic beyond the Continental 
according to Danish investigations. 
Anguilla rostrata by vertical, shadin 
(>6 cm.) larve of Anguilla vulgaris, 
of the coasts. 
(2) The elver fishing, such as we know in the 
rivers of West Europe, is in the Mediterranean 
only carried on in the western basin (West Italy), 
not further to the east. Just as in North Europe 
this indicates that the elvers decrease in quantity 
from west to east, and in the same way we may 
compare the scarcity or absence of eels in the 
Black Sea region with the similar condition in the 
inner Baltic or northernmost Norway. (3) A very 
extensive investigation has given the result 
that the North European, South European, and 
NO. 2234, VOL. 89| 
;. 2.—Distribution of the freshwater eels (Anguilla) and of their larvz in the Atlantic regions, 
Occurrence of Anguilla vulgaris shown by horizontal, of 
@ Younger (3}-6 cm.) and @ older 
larve of Anguilla rostrata recorded. The unbroken 
jines indicate the temperature at 1000 m. depth.—Johs. Schmidt (1909 and rg12). 
Slope, and that they must be in 
the Northern Atlantic. 
Confirmation of this conclusion 
has been obtained from two differ- 
ent sides. On a cruise over the 
| Atlantic in 1910 with the Michael Sars, Dr. Hjort 
has taken twenty-one eel larve south of the Azores, 
the majority of which were 1, a few even 2 cm. 
| smaller than the smallest I had found west of 
Europe in 1905-6. This was a most important dis- 
covery. Further, surface collections made by 
Danish vessels crossing the Atlantic, both fifty 
years ago and recently, have yielded a large mate- 
rial of these young larva. Our captures are shown 
on the chart, Fig. 2, from which it will be seen 
that larvae of the genus Anguilla occur across the 
