PELAGIA. 41 



In the present series the general condition of the canal system is that 

 described by Maas, the rhopalar canals being narrow, the tentacular canals 

 broad ; but there are no traces of any septal divisions in tlie tentacular 

 canals, a result also reached by Mayer (: 06). This I was able to establish 

 beyond doubt by examining all the canals in several excellent specimens. 

 Absence of adhesion areas in A. loyvillei suggests that the occurrence of such 

 structures in other species may prove to be a character of taxonomic im- 

 portance. The tentacular canals divide some distance before reaching the 

 base of the tentacle, a branch running into the lappet on either side, and 

 a third lobe extending to the base of the tentacle. This latter lobe ends 

 blindly at the base of the tentacle, as Maas (: 04") describes, but instead of 

 gradually dwindling, forms on the aboral side a definite pocket, which is 

 apparently the result of the extreme development of the tentacular mus- 

 culature, being squeezed down, as it were, between the muscular masses on 

 either side of it. 



No colored figure of A. loyviUei has previously appeared. The general 

 coloration (PI. 8, fig. 1 ; PI. 9, fig. 3) is the same which has so often been 

 described for other members of the genus, 



A. tvyvillei has previously been recorded only from antarctic and subant- 

 arctic stations. 



DiSCOPHORA. 



Only two representatives of this order were taken during the expedition, 

 — a Pelagia, and a species apparently belonging to the remarkable new 

 genus Poralia described by Vanhiilfen (: 02*) from the collection of the 

 " Valdivia." 



Pelagiidae. 



Pelagia Peron et Lesueur, 1809. 



Pelagiidae with 1x8 tentacles. 



I am in considerable doubt as to what specific name to apply to the 

 specimens of Pelagia in the collection. In no genus of Medusae is revision 

 more needed than in Pelagia; but most of the descriptions of the diff"erent 

 species are so unsatisfactory in regard to just those features which may 

 reasonably be supposed to be of specific importance, that any attempt at 

 rearrangement is hopeless, without the study of extensive collections from 

 all oceans. It seems certain, however, especially from the studies of Van- 

 hoffen (: 02") on the "Valdivia" collection, that not all of the fourteen 



