iiHizosTOMjE TURKU MA. r;j; 



Rhizottomata fripttra, continued 



Crambione MAAS, 1903. Similar to Crambcua, but with both clubs and filaments upon the mouth-arms. 

 Masttgias L. A'.ASSIZ, iS(i .Miiitii>ias + Kucrambessa HAKKM. Each rnouth-arm terminates in a naked club. 

 Numerous clubs or filaments among the mouths. The network of vessels which arises from the inner side 

 of the ring-canal connects with the stomach. 



Pitudorhiza VON LtNiii.Nt I.LD, 1882. Similar to .\fastigiat but without lateral clubs or filaments upon the 

 mouth-arms. A terminal club present. The canals which arise from the circular vessel, between the radial- 

 canals end blindly without reaching the stomach. 



PhyJlorhha L. AGASSIZ, 1862. Mouth-arms with lateral filaments, but without clubs as in Lychnorhiza. Canal- 

 system as in Mastigias. 

 Vessuru, HAM KM., 1880. Mouth-arms with clubs and filaments as in Crambione. 4 perradial canal 



directly from the stomach, but the 4 interradial canals result from the fusion of a network of vessels which 

 arise from each interradial side of the stomach. An outer and an inner zone of circular muscles with an 

 annular separation between them. 

 Lobonftna, gen. nov. Marginal lappets elongated to form tentacles-like organs. Mouth-arm membrai: 



orated by window-like openings. Exumbrella covered profusely with papill.r. 



Rkisostomata lorifera: 8 mouth-arms, very elongate, whip-like, and triangular in cross- sect ion, with frilled mouths 

 developed along the angular edges of the arms (fig. 4 117, p.(nji ! Thc( \ lmdric.il upper parts of the arms are rudimen- 

 tary and partially fused one to another by gelatinous arches spanning between them and connecting them \uih 

 arm-disk. The genera are as follows: 



Thysanostoma L. AGASSIZ, 1862. No terminal clubs on the mouth-arms. Mouths along the 3 angles through- 

 out length of arms. 



Lorifi'f/i, \\\\< KM., iSSo. Similar to Ttn'sanostoma, hut with a naked club at lower end of each arm. 

 Lefitobrachiii BRANDT, 1838= Lfptobrarhia -t- Leonura HAI.CKI i . M< milr-. confined to the upper and lnv i 



of the mouth-arms, leaving the middle part of the arm naked. 



Rhizostomata srapulata: Each mouth-arm bears a pair of simitar-shaped .ip(" ii.l.u-r ( i.ipulrt I which arise from tin- 

 outer side near the base of the arm and bear frilled mouths (fig. 421, p. 697). The circular muscles of the sulnimhn II a 

 are powerfully, and the radial-muscles weakly, developed, or even absent. The genera are av (..!! 



Rhbustoma CUVIKR, iBoo^Piltma HAK.KKL, 1880. 8 free mouth-arms, the lower parts of which are Y-slnped, 

 or 3-wingcd, in cross-section. Each arm terminates in a naked club. There are no other clubs or filaments. 

 Rhopiicrrut HAM KM, iSSo. Similar to Rhizostoma but with numerous clubs or filaments upon tin* mouth-arms. 

 Euftilema HAKCKKL, 1880. Similar to Rhizostoma, but the arms have neither clubs nor filaments. 

 Stomohpkui L. ACASSIZ, \$()2=BrachiolQf>hus+StomoIof>hus ) MA>CK>I, iSSo. The 8 mouth-arms ai- 



along their sides leaving only the lower ends free and forming an < luiHMie throat-tube for the ti-ntr.il mouth 

 which remains open. 

 Rhizostomata simplicia: Rhizostoma' with unbranched mouth-arms. These apocryphal forms arc described by H 



and by Fewkes from alcoholic specimens of small size. They are apparently immature or injured specimens. V* 

 naturalist lias seen any of these forms since Fewkes described Ins " Xivmotontma rtticulatum" in iSS4_ It is probable 

 that we should drop these medusa? from further consideration, but in the faint hope that some may be discovered 

 I have given descriptions of them based upon the statements of Haeckel and Fewkes. 



RHIZOSTOMATA PINNATA Vanhbffen. 



Rhizostomata pinnata, VANHOFFKN, 1888, Bibliothcca Zoologica, Bd. I, Heft. 3, p. 40. MAAS, 1903, Scyphomcdusen der Siboga 



Kxped., Monog. n, p. 38. 

 Cassiopeida t CLAUS, 1883, Organisation und Entwick, Medusen, Leipzig. VON L>MM n n, 1888, Zeit. fur \vissen. /.""I.. H.I. 



47, p. 211. 

 Arfadomyaria, MAAS, 1903, Scyphomcdusen der Siboga Exped., Monog. n, p. 88; 1907, Ergeb. Portschritte der Xool., Bd. i, 



p. 201; 1906, Revue Suisse de Zool., tome 14, p. IOO. 



Rhizostomous medusae with 8 linear, pinnately, or complexly branching mouth-arms. 



GENERA. 



Toreuma Haeckel, 1880. 8 rhopalia. 



Cassiopea Pcron and Lesueur, 1809. More than 8 rhopalia. 



Genus TOREUMA Haeckel, 1880. 



Toreuma, HAECKEL, 1880, Syst. der Medusen, p. 566. VANHUFFEN, 1888, Bibliotheca Zoologica, Bd. i, Heft. 3, p. 40.- M \->- , 

 1903, Scyphomcdusen, Siboga Exped., Monog. n, p. 43. 



The type species is Toreuma dieuphila y described by Peron and Lesueur from the Indian 

 Ocean. 



GENERIC CHARACTERS. 



Rhizostomata pinnata with 8 adradial, linear mouth-arms which branch pinnately or 

 complexly, and the main side branches also branch. 8 marginal sense-organs. 



This genus is closely related to Cassiopca and is distinguished only by having 8 rhopalia, 

 whereas Cassiopea has more than 8. Haeckel is the only modern naturalist who has seen 

 any of these forms. They all come from the Indian Ocean. 



