9 
bands have been compared in detail with the normal. In general the 
decapitated conform. to the pattern of the normal. The chief point 
of dissimilarity is that the dark bands are poorly defined, are narrow 
and less dense owing to the contracted chromatophores which now 
give to the larvae a bleached appearance. 
Larvae 24-25 mm. In general coloration the larvae are now 
much darker as is fairly well shown by Fig. 4. The pigmentation 
of the head is denser, but there is still present a median light band 
extending from the tip of the nose to the tip of the tail. There is 
also an indistinct light band extending backward from the region 
just above and in front of the eye to the level of the gills where it 
becomes continuous with a well defined light lateral band. This extends 
to the level of the posterior limbs where it becomes indistinct. Just 
below this light band there is a broad irregular dark band extending 
from the nose to the gills. From the gills this same band extends 
to the tip of the tail. Here it shades off irregularly on its ventral 
surface and is interspersed with small clear oval or round areas which 
give rise to a mottled appearance. 
The decapitated larvae of this stage (Fig. 5) show a much wider 
median light band in the mid-dorsal region. Just below and outside 
of this there is on either side a narrow pigmented band which extends 
from the level of the gills to the level of the posterior limb where 
it fades out. The light band lying just below this is much wider. 
It extends slightly beyond the level of the posterior limb. This band 
is much wider than the normal and its margins are better defined. 
Below this light band is a second dark band which extends from the 
level of the gills to the tip of the tail. It is much narrower than 
in the normal and its margins are irregular. 
The migration of the chromatophores and their later arrangement 
in bands and areas are in all essentials the same as in the normal. 
It should be emphasized that the first bands of pigment coincide with 
the large dorso-lateral blood vessels. The later formed bands and 
areas, however, bear no fixed relations to blood vessels. 
Growth and regeneration of gills. 
The growth and regeneration of the gills in the normal embryo 
have been carefully studied by the writer and the results published 
in an earlier paper (Biol. Bull. 1906). It would therefore be super- | 
fluous to repeat the details here. They, however, afford the basis for 
