30 THE VOYAGE OF H.M.S. CHALLENGER. 



collar in the Cunanthidse becomes rounded, the shorter is the double canal, which 

 connects the free-arched margin of the annular canal with the radial gastral pouch, and 

 the longer at the same time the festoon canal, as we may suitably term the annular 

 canal, with its bow-shaped archings inwards. However isolated this formation of the 

 vascular system in the Cunanthidse may appear at first sight, it may easily be re- 

 ferred back to that of some of the closely allied Trachomedusse (especially the Geryonidse). 

 In these Geryorddae, in which the flat " genital layers," or pouch-like broadened radial 

 canals only reach to the annular canal, we only require to insert the indentation of the 

 umbrella margin deeper into the opening place of the annular canal, and to represent 

 the umbrella clasps as running straight through to the basis of the tentacles, in order 

 to have the formation of the Cunanthidse. The annular canal of the Geryonidse (and of 

 the remaining Craspedotse) consequently corresponds to the entire " festoon canal " of the 

 Cunanthidse, which is composed of the double peronial canals and the peripheric " mar- 

 ginal canal " (lying on the marginal urticating ring), which connects them. On the 

 other hand, the four broad perradial " gastral pouches " of Cunantlia and Cunarcha cor- 

 respond to the four typical " radial canals " of the Craspedotae, which are also sometimes 

 extended like a ribbon (as, for example, Liriopc and Glossocodon). The two lateral 

 wings of the last, in which the sexual products develop, may also be compared to the 

 two sexual "lobe pouches" of Cunarcha (comp. my System der Medusen, 1879, pp. 

 304, 306, taf. xix. fig. 2 ; taf. xx. figs. 1, 2). The paired lobe pouches of Cunarcha and 

 Cunoctantha (I.e., taf. xx. figs. 1, 2) are at the same time nothing else than the " inter- 

 nemal gastral pouches " of the iEginicke (I.e., taf. xx. fig. 11). Cunarcha therefore appears 

 to be a very interesting phylogenetic intermediate form between Cunantha and AZgina, 

 immediately connecting these two tetranemal parent genera of the Cunanthidae and 

 iEginidse with each other. (Comp. the tabular " Uebersicht liber die Homologien der 

 Kadial- Canal e einiger tetranemalen Trachomedusse and Narcomedusse " in my System der 

 Medusen, 1879, p. 336.) 



Family, Peganthid^e, Hseckel, 1877. 

 PEGAKTHiDiE, Hteckel, System der Medusen, 1879, p. 323; taf. xix. figs. 4-7; taf. xx. figs. 14, 15. 



Narcomedusse without radial canals and without gastral pouches in the subumbrella, 

 but with a festoon canal (or a circular canal formed by a circle of separate lobe canals), 

 with otoporpce or auditory clasps at the basis of the auditory clubs. 



Sub-famdy, Polyxenid.e, Hseckel, 1877. 



Peganthidae with a single circular genitalium, forming a simple or lobed girdle in 

 the subumbral wall of the stomach. 



