132 



THE PINEAL ORGAN 



The central eyes of scorpions resemble the central pair of Limulus 

 in having a single biconvex, cuticular lens beneath which is a continuous 



p2 p . 



Fig. 93. — Diagram showing the Median and Lateral eyes of a Scorpion, 

 and their connection with the " brain," or supra-cesophageal 

 Ganglion. 



Hrt. : heart. 



Int. : intestine. 



L.E. : group of lateral eyes, connected by a common optic nerve with the 



supra-oesophageal ganglion. 

 M.E. : median eye, also connected with the supra-oesophageal ganglion. 

 P. Gl. : poison gland. 

 P l : pulmonary sacs. 

 P 2 : pulmonary sacs. 

 P 3 : pulmonary sacs. 

 P 4 : pulmonary sacs. 



nerv. 



Fig. 94. — Section through a Lateral Eye of Euscorpius Italicus. 



int. : intermediate cells. 



lens : single cuticular lens. 



nerv. c. : nerve-cells. 



nerv.f. : nerve-fibres, of optic nerve. 



rhabd. : rhabdomes. 



layer of columnar cells (Fig. 95). The retina is, however, composed of 

 retinulae disposed in groups, as in the composite eyes of insects and 



