269 



PART IV. 



VENOMS IN THE ANIMAL SERIES. 



CHAPTBE XVI. 



l.—INVEBTEBBATES. 



Besides reptiles, many other animals possess poison-glands 

 and inoculatory organs which they employ, either to defend them- 

 selves against their natural enemies, or to capture the living prey 

 upon which they feed. 



The venoms that they pro'duce are still, for the most part, but 

 little understood. A few of them, however, have excited the 

 curiosity of physiologists, especially those secreted by certain 

 batrachians, such as the Toad, and certain fishes, such as the 

 Weeve?: Some of them exhibit close affinity to snake-venom, and 

 are composed, like the latter, of proteic substances modifiable by 

 heat and precipitable by alcohol ; others possess altogether special 

 characters, and resemble alkaloids. 



The lowest animal group in which these secretions begin to be 

 cleanly differentiated is that of the Goelenterates. 



A. — Goelenterates. 



It has been shown by Charles Eichet' that the tentacles of sea- 

 anemones (Anemone scuUata) contain a toxic substance which has 



' Comptes rendus de la Socie'te de Biologie, December 13, 1902 ; June 6, 

 July 25, 1903; February 20, 1904. 



