LATERAL AND CENTRAL EYES OF SCORPIO AND LIMULUS. 177 



The Minute Structure of the Lateral and the 

 Central Eyes of Scorpio and of Limulus. 



By 



E. Ray l<ankester, H.A., F.R.S., 



Jodrell Professor of Zoology, 



and 

 A. G. Bourne, B.Sc* 



With Plates X, XI and XII. 



Scope. — In the essay entitled *' Linnulus an Arachnid,'^ 

 published in this Journal in 1881, it has been pointed out by 

 one of us (Prof. Lankester) that, amongst other very numerous 

 agreements of structure exhibited by the Scorpions on the one 

 hand and the King Crab on the other, there is a close super- 

 ficial coincidence in the disposition and the character of the 

 eyes ; in both we find a single pair of simple central eyes, 

 and a lateral or marginal pair of '^ grouped " or aggre- 

 gated eyes — the multicorneal lens of the King Crab's lateral 

 eye corresponding to the numerous (two to seven) small lenses 

 placed in groups laterally on the Scorpion's head. 



The object of the investigation, of which the present memoir 

 records the results, was to ascertain how far there is a real 

 identity in the minuter structure of the eyes thus compared, 

 and what precisely is the morphological relationship between 

 the multicorneal lateral eye of Limulus and the groups of 

 unicorneal eyes occupying a corresponding position in the 

 Scorpions. 



The evidence adduced in the essay above cited in favour of 

 a close genetic relationship between tlie King Crabs and the 

 Scorpions was so overwhelming and convincing to our minds, 

 that we entered upon this inquiry with the strong anticipation 



VOL. XXIIl. — NEW SEll. M 



