47 
can be determined with certainty, but through the kindness of the 
authorities at the Zoological Museum of Upsala I have been able 
to examine his type specimens; in this way it has been possible 
to determine their characters and thus to avoid making new names. 
On counting the vertebræ I found that his Leptocevhalus Eckmani 
is identical with a species occurring in immense quantities in our 
gatherings, especially in the Atlantic west of the Azores. In the 
Mediterranean a very similar form was described many years ago 
under the names of Leptocephalus diaphanus and Leptocephalus 
inornatus. To determine whether the two forms from the Atlantic 
and the Mediterranean had anything to do with each other, however, 
necessitated a comparison of numerous specimens, including counting 
of vertebræ. It then appeared that the two forms are very closely 
related, so closely that it is doubtful whether they can be always 
distinguished when the place of occurrence is unknown. The number 
0 vertebræ is not absolutely different, as the same number may 
be found in specimens from the Atlantic and Mediterranean, but on 
an average the number of vertebræ in the form from the Atlantic 
is 2—3 more than in the form from the Mediterranean. Further, 
the head of the latter is a little stouter and the rows of pigment 
Spots between the myomeres are a little more marked, containing a 
few more spots. The Atlantic form is, numerically, by far the most 
important of all eel-larvae in our collections, showing that it must 
have a very wide distribution. It has been taken off the continental 
slope of the western part of the Atlantic from Newfoundland to 
Guiana and eastwards it ranges to near the Azores. It occurs in 
largest quantities between 50? and 70% W. Long., taken at the 
Surface over the greatest oceanic depths. H. M. S. Ingolf” which 
has made collections for us, took no fewer than 477 specimens in 
our Atlantic Leptocephalus specimens of C. balearicus, but the de- 
seription of the two American naturalists is not sufficient to pens 
an identification. 
