3. On the Hermaphroditism of Fixed Animals. 105 



into separate sexes, it is manifestly bound up in the majority of animals with widely different 

 habits of life, so that the males and females of most species fill a different role in the economy 

 of their species with regard to almost every vital function besides that of reproduction. In 

 fixed animals which are by the fact of their fixation destined to a more or less dull routine 

 of existence in which the vital functions have only to perform a few stereotyped duties, this 

 elaborate differentiation of the sexes has been lost. In this manner we may look upon the 

 hermaphroditism of fixed animals as part of the general degeneration which they have mani- 

 festly undergone in all other respects. 



Without entering further here into a subject which formed the chief theme of the last 

 chapter, I would emphasise that point of view which regards the sexual organization of every 

 animal not merely as an adaptive means of propagation, but also as a regulation of the meta- 

 bolic activities in the animal itself, irrespective of the production of a new generation. The 

 phenomena of sex are so intimately bound up with those of assimilation, growth and differen- 

 tiation, that we cannot hope to gain any complete explanation of their variations in different 

 animals by simply regarding them as a mechanism for ensuring the production of young, while 

 ignoring their relation to the metabolic activity of the body which exhibits them. 



List of Literature. 



1. Fraisse, P., Die Gattung Cryptoniscus. in: Arb. Z. lust. Wiirzburg 4. Bd. 1S78. 



2. Mayer, P., Carcinologische Mittheilungen. 6. Liber den Hermaphroditismus bei einigen Isopoden. in: 



Mitth. Z. Stat. Neapel 1. Bd. p. 165 1S79. 



3. Kossmann, R., Neueres iiber Cryptonisciden. in: Sitzungsb. Akad. Berlin p. 547 1SS4. 



1. Maupas, E., Modes et formes de reproduction des Nematodes, in: Arch. Z. Exper. 3) Tome 8 p. 463 1900. 

 5. Bonnier, J., Contribution a l'etude des Epicarides. in: Trav. Stat. Z. Wimereux Tome & 1900. 

 0. Hansen, H. J., Isopoden, Cumaceen und Stomatopoden der Plankton-Expedition. Kiel und Leipzig 1S95. 

 7. Caullery, M., & F. Mesnil, Recherches sur Y Hernial riscus balani. iu: Bull. Sc. France Belg. Tome 34 

 p. 310 1901. 



Zool. Station zo Neapel, Flora und Fauna, Golf Ton Neapel. Ehizocephala. 14 



