282 THE LARVA OF THE EEL. 
rocks or at great depths and seek shallower water. It is obvious 
that this suggestion has no great air of probability. 
The careful experimental investigation of the Leptocephali was 
carried on by these naturalists in the year 1591—2, and the follow- 
ing were the results. In the development of the conger (Conger 
vulgaris) three stages can be distinguished :—First, a teenioid form 
resembling LD. Morris, except that the dots on the lateral line are 
limited to the posterior extremity of the body; second, L. Morrisw 
itself ; and third, the form which had been previously distinguished as 
L. punctatus : from this the perfect conger is directly developed. 
The first teenioid form has long and fine larval teeth; these are 
wanting in Morrisii, in which the permanent teeth begin to develop 
in a position internal to that of the larval. 
During the metamorphosis there takes place a gradual reabsorp- 
tion of the gelatinous skeleton, much pigment develops, the anus 
passes into a more anterior position, and so much diminution in size 
takes place that from larve 124 cm. long (5 inches) are obtained con- 
gersonly 7$cm., (3 inches). During the transformation, which may not 
take more than a month, the Leptocephali take no food or only 
minute particles. The transformation may be followed without any 
difficulty in specimens kept in any aquarium, or even in tubs; the 
authors observed it in 150 individuals. This is surely a sufficient 
confirmation of the isolated observation of Delage. All the various 
stages observed in captive specimens were also seen in specimens 
taken from the sea. In the aquaria the larve hid away in groups, 
threaded through the crevices under stones, the eggs of Aplysia, 
&c.; they also sought the darkest corners of the aquaria and avoided 
the hght. 
Li, diaphanus of Kaup was found to develop into Congromurena 
balearica. This is a Mediterranean species of Congromurena, 
a genus very similar to Conger, but distinguished by the presence of 
large muciferous cavities in the front part of the skull, and the 
dorsal fin commencing at a more anterior point, namely, nearly above 
the gill opening. L. Kéllikert proved to be the larva of Congro- 
murena mystax, the only other Mediterranean species of the genus ; 
and LI, Haeckel, Yarrellii, Bibroni, Gegenbaurt, and probably 
brevirostris were found to be merely different stages in the de- 
velopment of the same form. The investigators have now come to a 
different conclusion concerning brevirostris, but with regard to the 
others reference to Kaup’s original descriptions and figures shows 
that they resemble one another in the truncated, rather broad form of 
the tail and its distinct rays. In the course of development it 
appears that the post-anal or caudal portion of the body continually 
grows longer in proportion to the pre-anal or anterior portion. It 
