ENDOCRINOLOGY OF INVERTEBRATES, PARTICULARLY 

 OF CRUSTACEANS* 



L. H. Kleinholz 

 Reed College 



Many of the early studies in comparative endocrinology were under- 

 taken to seek among the invertebrates endocrine functions analogous to 

 those known for the vertebrates ; but few substantial contributions re- 

 sulted, probably because the normal physiolog}^ of a particular process 

 among invertebrates was inadequately established. The decade between 

 1920 and 1930 saw demonstrations of hormonal factors in physiological 

 processes of invertebrates in which the pattern and direction of research 

 for a number of years to come was indicated. The first of these was Kopec's 

 (1922) report that removal of the brain from the last instar larva of 

 Lyniantria resulted in a failure of pupation to occur ; when the brain was 

 reimplanted into the abdomen, pupation was initiated. Perkins (1928) 

 and Koller (1928) almost simultaneously demonstrated that the chro- 

 matophores of crustaceans were regulated by a blood-borne substance 

 originating in the eyestalks, instead of by nerves, as had been postulated 

 up to that time. 



The lively activity set off by these early studies has resulted in such a 

 large and specialized body of literature in the area of invertebrate endo- 

 crinology that it would be impractical for one person to attempt a critical 

 review and survey of this field. This subject has consequently been divided 

 into a number of topics which can conveniently be reviewed by the speak- 

 ers and participants of this symposium. I shall discuss the general endo- 

 crinology of invertebrates, particularly of crustaceans, Bodenstein will 

 survey the endocrine basis of growth and development in insects, Welsh 

 will analyze the function of neurohormones in invertebrates, and Scheer 

 will discuss the metabolic aspects of molting in crustaceans. 



The classical criteria in investigations of endocrine problems of verte- 

 brates (i.e., removal of the gland suspected of endocrine function, ob- 

 serving the interference with a normal physiological process as a conse- 

 quence of such gland removal ; obtaining a restoration of the normal pro- 

 cess by the implantation of such glands, or by the injection of extracts or 

 separated fractions of extracts prepared from these glands ; demonstra- 

 tion of the effective substance in the blood) can be expected to apply in 



* This manuscript was prepared during the tenure of a grant, G-1395, from the 

 National Science Foundation. 



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