426 
W. N. F. WOODLAND. 
The Nauplius Eye. 
The Nauplius eye persists in the adult Squilla, and can 
easily be seen under a low-power binocular as a small patch 
of black pigment lying towards the ventral side of the head 
between the bases of the paired stalked eyes. The pigmented 
eye apparently contains in the specimens examined either 
two or three ocelli (probably three, since this is the number 
found in most Crustacea), and is connected by a single slender 
nerve to the brain. 
Appendix. 
Methods of Preparation of Material . 
The adult specimens of Squill a desmarestii were fixed 
for me at Naples in Hermann's fluid, in Zenker^s fluid, in 
corrosive-acetic and in hot absolute alcohol. On receiving 
them I carefully decalcified certain specimens in a mixture of 
nitric acid (over 5 per cent.) in alcohol (the liquid constantly 
renewed) for three or four weeks. They were then em- 
bedded in hard (60° C.) wax and cut into sections 10 thick. 
Despite the thickness of the cuticle, complete series of trans- 
verse and longitudinal vertical sections were obtained of 
three entire animals. Complete series of transverse and 
longitudinal sections were also made of many larva3 of the 
sizes mentioned in the above description. All these sections 
were double-stained on the slide in Ehrlich’s hmmatoxyliu 
(twenty-four hours), followed by picro-indigo-carmine. (Add 
one part saturated solution of picric acid in 90° alcohol to 
two parts saturated solution of Griibler’s indigo-carmine in 
70 per cent, alcohol, and dilute this stain with equal bulk of 
70 per cent, alcohol; for mode of using this stain see my 
paper on ^^Fish Gas Glands,” ^ Proc. Zool. Soc. Lond.,’ 1911.) 
Sections of the Hermann’s fluid material were found to be 
best preserved. 
