NAUPLIUS EYE PERSISTING IN SOME DECAPODS. 283 
On the Nauplius Eye persisting in some 
Decapods. 
By 
Margaret Robinson, 
University College, London. 
With Plate XIV. 
Tue nauplius eye has been described as persisting in Schizo- 
pods, but I have heard of no description of it in Decapods, 
though Dr. Paul Mayer mentions having seen it in an adult 
Palemonetes (‘Carcinologische Mitt. Naples Mitt.,’ vol. 11). 
Professor Weldon noticed it in Palemon, and suggested that 
I should work it out either in that or in some other member 
of the Carididz. This is the only family in which I know of 
it as persisting. I have used Palemon serratus, Virbius 
varians, and Pandalus annulicornis. 
External Appearance.—On removing the rostrum from 
a fresh specimen the median eye can be seen as a black speck 
lying in the centre of the triangle formed by the brain and 
the stalks of the lateral eyes. In preserved specimens it is not 
quite so obvious. I have made a dissection of the brain of 
Pandalus annulicornis (fig. 13), in order to confirm the 
results obtained from sections. 
On removing the rostrum one sees the speck lying in the 
centre of the above-mentioned triangle. There is chitin 
covering the brain, and this chitin is connected by means of a 
