NAUPLIUS EYE PERSISTING IN SOME DECAPODS. 285 
end cells. This arrangement obtains also in Palemon and 
Pandalus. 
Pigment Cells.—These are two large cells placed side by 
side so as to form an ¥. In Pandalus and Virbius the diver- 
gence of the arms is slight, but in Palemon it is considerable 
(thus X ). 
By partially depigmenting the sections with chlorine dis- 
solved in alcohol it can be seen that the nuclei lie in the 
ventral halves of the cells and far forward. 
Nerve-end Cells.—In transverse sections the nerve-end 
cells appear to be arranged in three groups, of which two are 
lateral and one ventral to the pigment cells. 
On counting the nuclei I find that there are almost invari- 
ably six cells in each of the lateral groups, and two in the 
median ventral group, making fourteen in all, The cells in 
the ventral group are continuous on either side with those of 
the lateral groups, and through them are connected with the 
ectoderm anteriorly, while posteriorly all three groups are 
continuous with the “ Punkt-substanz” of the brain. Inall the 
genera which I have examined the cells are club-shaped in 
horizontal section. 
Muscles.—On the outside of each band of supporting 
ectoderm, between that and the outermost ectoderm, is a band 
of muscles. I have traced these muscles back to where the 
circumeesophageal commissures are given off from the brain, 
and have seen that they slope inwards and ventralwards from 
the outside ectoderm to the centre of the brain. I think that 
their function must be to help in casting the chitin from the 
brain at the moult. 
I can find no trace of a refractive body within the eye, but 
in the posterior sections where anteriorly the ectoderm is 
thickened there is a groove filled with chitin lying dorsal 
to the eye. 
