THE DEVELOPMENT OE S mBLiANCHUS MARMORATUS. 3 
‘^movement of the is taken verbatim from liis notes. 
I should like to take this oppoi-tuuiby o£ thanking Dr. Agar 
for placing this unique material unreserv^edly at ray disposal, 
and for the kind interest he has shown in the progress of the 
research. 
My best thanks are offered to Professor Grraham Kerr, in 
whose laboratory much of the work was done, and who has 
helped me throughout with constant advice and criticism. 
I am greatly indebted to S'"' Veronica, S.N.D., for her 
artistic illustrations. 
Symbranchus, like many fishes and amphibians, exhibits 
the phenomenon of colour-change in response to alteration in 
the conditions of light and darkness, specimens fixed at 
niff lit beinsf lia*hter in colour, because of the contraction of 
the chromatophores, than those fixed in daylight. The living 
larvae actively burrow among the weeds at the bottom of the 
rearing tanks when the lid is removed — as though to escape 
from the light. 
A bout a dozen nests in all were found, the adult male, as in 
the case of Lepido siren, being present to guard the contents. 
In many other respects the nesting habits of Symbranchus 
resemble those of Lepidosiren. 
The Avater in the swamps where the eggs were found was 
commonly from one to four feet deep. The mouth of the nest 
opens on the bottom of the swamp and leads into a tunnel 
running obliquely downAvards into the mud. At the end the 
tunnel takes a more or less horizontal direction, and it is in 
this part that the eggs are laid, there being little or no Aveed. 
The eggs are translucent, and of a greyish colour. It is 
quite impossible to assign a definite age to the contents of 
any one nest, as the eggs may show every variety in state of 
development from “early segmentation^^ to “moving 
embryos.” Neither is it possible to give any definite idea of 
the rate of development before hatching. However, in a nest 
discovered on December 12th the eggs were of fairly uniform 
and of early stage (Stage 5). Some of these hatched out on 
the 19th, the resulting larvm being of the stage described as 
