1 8 C. V. MORRILL, JR. 



The lost vitreous humor is apparently, made good in some way. 

 An examination of the eye at the end of the experiment (after 

 ten weeks) revealed not the slightest indication of a new lens. 

 Regeneration of the lens in Triton and Salainaiidra, has been 

 obtained by Colucci ('91), Wolff ('95) and Fischel ('98). These 

 results cannot then be extended to the teleost, Fundiilus lictero- 

 clitns. However, it still remains to be shown whether the re- 

 generative powers of the eye are not better developed in other 

 species of teleosts. 



SUMMARY AND CONCLUSIONS. 



The general conclusions to be drawn from the foregoing ex- 

 periments are the following : 



1. In Fnnditlus lictcroclitus the dorsal, caudal, anal, pectoral 

 and pelvic fins \vill regenerate even when cut off close to the 

 body, provided the proximal ends of the dermal fin-rays remain 

 in situ. No regeneration takes place except when the stumps 

 are present, and of sufficient size. 



2. The operculum does not regenerate. 



3. The lower jaw completes itself if a piece is removed. 



4. The scales, if carefully removed, are quickly replaced by 

 others. 



5. The eye does not regenerate a new lens. 



The results on the regeneration of fins support in general 

 Broussonet's earlier work and that of subsequent writers. The 

 ability to regenerate a portion of the jaw has been found by 

 Spallanzani (1768) and others in the salamander. The lack of 

 ability to regenerate a new lens in Fnnduhis, however is peculiar, 

 since the salamander, an animal of a higher order, possesses it to 

 a marked degree. It would be interesting in this connection to 

 test the regenerative powers of the eyes of elasmobranches and 

 ganoids, as being more generalized types than the teleosts. 



In regard to Broussonet's statement that those fins which are 

 the most useful, regenerate the quickest, it seems more probable 

 that the conditions of the cut, as described for each experiment 

 above, are the factors which determine the rate of regeneration, 

 given equal conditions of temperature, food, vitality, etc. Indeed 

 it is difficult to estimate the relative rate of growth, for in any 



