Regeneration in Compound Eyes of Crustacea 173 



the mouth parts. This shows that the effects are not specific- 

 ally connected with operations upon the eye. Whatever its ini- 

 tial cause the effect is transmitted to the whole nervous system. 



In many cases the operation seemed to affect the animal more 

 seriously when only the upper part of the eye was removed than 

 when the entire eye was cut off. Frequently the relative number 

 of survivors was greater in the latter than in the former case. In 

 other instances the animal did not seem greatly affected by the 

 operation regardless of whether the whole or a part of the eye was 

 removed. (See Table I.) 



The immediate visible effects upon the eye may be briefly 

 described as follows. As soon as any part of the corneal covering 

 is removed or even as soon as a rent is made in it a considerable 

 amount of the soft, viscous, inner tissue flows out through the 

 opening. It is perhaps carried out by the escaping blood. Much 

 of the pigmented, retinular tissue seems to escape, perhaps because 

 it is softer and more viscous than the other tissues. After an hour 

 or so the remaining, inner tissues are seen bulging out and above 

 the general level of the surface. This is probably on account of 

 the destruction of the normal tension of the tissues due to the 

 changed pressure conditions at the wounded surface. A similar 

 appearance is obtained when the surface injury consists of a rent 

 torn in the cornea with a needle. 



A HEALING OF THE WOUND AND FORMATION OF NEW CUTICLE 



In a few hours after the operation most of the pigmented tissues 

 have disappeared from the surface of the wound and the swollen 

 surface takes on a whitish appearance. This white swollen surface 

 is apparent for several days. Not until the fourth or fifth day is 

 there any sign of the characteristic red-brown crust which generally 

 forms over wounds in Crustacea. 



Sections of an eye fixed six and a half hours after the operation 

 show no definite indications of the healing of the wound. A 

 great deal of the broken and mangled tissue lies outside the wound 

 and hanging to the cuticle about its edges. Inside, the tissues are 

 twisted and misshapen. At the edges of the wound there are 



