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than the present larva. There now remain Muraena unicolor and 
Chlopsis bicolor of the eel-fishes known in the Mediterranean. 
Aceording to Grassi the former has 136—140 vertebrae, whilst 
the latter according to Supino has 133. 
This shows already, that our larva belongs to Chlopsis and 
the position of the anus so far forward also indicates this. This 
position is found in C/lopsis, whereas in Muraena unicolor the 
anus is placed further back, and we have no cases among Lepto- 
cephali of the anus moving backwards during metamorphosis. The 
position of the nostrils also corresponds to the condition in Chlopsis, 
as also the tubular, anterior nostril, a feature that can be quite 
well: detected in the oldest of my larval specimens. Lastly, the 
structure of the tail in the larva agrees with that in C//opsis. 
Both the last and second-last hypural elements are broad plates 
the last bearing 5 or 4 and the second-last 3 or 4 rays. 
Among all the characters I have examined, none stands in 
the way of referring the larva to Ch/opsis; on the contrary, they 
all show agreement. The fact that the larva has large pectoral 
fins (without rays), whilst such are wanting in ChAlopsis, is not 
different to what we find in the larvae of other eel-fishes without 
pectorals, for example Nettastoma melanurum. 
According to our investigations with the ""Thor”, Cålopsis 
Occurs in all basins of the Mediterranean and it must be one of 
the commonest species. (It seems to belong to the Muraenoids 
which spawn in summer and autumn). It is remarkable, there- 
fore, that the larva has not been found at Messina by the Italian 
naturalists, who have made such rich collections of Leptocephali 
there; but it does not occur either in the collections of Lepto- 
Cephali from Messina, which I have at my disposal. 
To the same type as the larva of Chlopsis bicolor belongs 
Leptocephalus hyoproroides, described by Stråmman from the 
western part of the Atlantic, of which I have had the opportunity 
fo examine the original specimen through the kindness of the 
