41 
The pigmentation, wliose diagnostic importance in the Lep- 
tocephali was sufficiently pointed out by the Italian Bellotti (1883), 
is very characteristic and makes it possible to distinguish the three 
species occurring in our territory at a glance. They all have 
pigment along the gut, at the end of the tail and between this 
and the anus along the base of the anal fin; but from the pigment 
on the sides alone the species may easily be distinguished. Conger 
mystax does not have this pigment, C. vulgaris has a row of rather 
large round spots and C. balearicus has short rows of fine points 
on the boundaries between the muscular segments. C. balearicus 
besides has large isolated patches on the dorsal margin which are 
lacking in the other species. The number of myomeres which 
corresponds to the number of vertebræ in the species in question is 
also different, in C. vulgaris ca. 158, in C. mystax ca. 138 and 
in C. balearicus ca. 130. 
The ca. 1—2 cm. long larvae of C. vulgaris and C. mystax 
have been taken by the “Thor” in quantities in the Mediterranean, 
but it was only by means of long series of intermediate stages, up 
to a length when the number of vertebræ could be determined with 
certainty, that we have been able to identify them. In figs. 2 and 4. 
these stages of the two species are represented from specimens 
which were so well preserved that they could be microphotographed. 
It is easily seen from the figures, that the larva of C. vulgaris 
differs from C. mystax by ha vin g a shorter snout and a longer tail; 
further, the pigment patches along the gut are much doser together 
in the latter than in the former and C. mystax also has some 
pigment spots at the point of the lower jaw which are wanting in 
C. vulgaris . Of C. balearicus I have not seen stages smaller than 
ca. 2 l h cm. and these are already so characteristic, owing to the 
pigment on the sides, the dorsal pigment and the position of the 
anus, that they cannot be coufused with other species. A fourth 
species of Leptocephalus, of unknown parentage, will be described 
later; meanwhile, I may just briefly discuss the distribution and 
biological conditions of the above three species, for which both the 
