Organism of the Sipho7iophora. 195 



custom, without any sufficient reason, wishes to make a 

 number of old names which have obtained a footing in science 

 disappear. Not only are new designations given to the orders 

 and to many families and genera, but a new nomenclature is 

 introduced, quite unnecessarily, for the parts and appendages 

 of the Siphonophora. 



In accordance with the fiction of the Medusome-notion all 

 organs whicli may have originally belonged to a Medusa- 

 person are comprised as a " Medusome," and palingenetic are 

 distinguished from c^nogenetic Medusomes. In the former 

 the chief organs are considered to have remained more or less 

 in their original connexion, while in the latter they have been 

 more or less dislocated in consequence of csenogenetic dis- 

 placement, and a secondary increase of homologous parts, a 

 " multiplication " of the organs, has taken place. Groups of 

 correlated Medusomes are denominated cormidia^ and these 

 are distinguished as ordinate ( Cormidia ordinatd) when they 

 are repeated in metameric sequence, and dissolved {Cormidia 

 dissoluta) when they are scattered on the stem and their 

 organs are separated from each other. The swimming column 

 is henceforth to be called the " Nectosome," the stem fol- 

 lowing beneath this the " Siphosome," the swimming-bell the 

 '* Nectophore ; " the gastric sac or nutritive polyp is re- 

 christened "Siphon," and the feelers (taster) " Palpons ; " 

 the filaments [Fangfaden) are called " Tentacles " *, the ter- 

 minal threads on the urticating nodes " Tentilla," the sub- 

 sidiary filaments of the taster " Palpacles," the tentaculiform 

 appendage with a terminal aperture " Cyston," the covering 

 pieces " Bracts," the taster or gastral tube bearing sexual 

 buds " Gonostyle," and the sexual buds themselves " Gono- 

 phores." In the air-chamber or pneumatophore we find the 

 air-sac denominated the " Pneumatosaccus," the air-flask the 

 " Pneumatocystis," its lower part which functions as a gas- 

 gland the " Pneumadenia," and the basal aperture or funnel 

 of this the " Pneumatopyle." That Haeckel makes a very 



* In my writings I have repeatedly made use of the expression " ten- 

 tacles " as synonymous with " tasters," just as ihe " feelers " of the Mol- 

 lusca are usually called "tentacles." With Haeckel, who designates the 

 " stinging filaments " as tentacles, this different use of the word leads to 

 the following logical conclusion :— " Not unfrequently palpons are con- 

 fused with tentacles, as, for instance, repeatedly by Claus, even in Physo- 

 phora" ('Report,' pp. 17, 193, 260). A glance at my memoirs, and 

 especially that on Hulistemma (1878), wiU at once convince any one that 

 I use " tentacle " as synonymous with " taster," and adopt the two deno- 

 minations indifferently, so that there can be no question of a confusion 

 with '* stinging filaments." Moreover it is quite incomprehensible how 

 any one could confound the " tasters " with the *' stinging filaments," 

 especially in Physophora, 



