RHIZOSTOM,E — RHOPILEMA, EUPII.KMA, STOMOLOPHUS. 709 



1904, where it was swimming near the surface on a cahn morninfi. The fishermen 

 informed me that it is seen (juite fretiuentl)- in Pamlico Sound in autumn. I lielicve, there- 

 fore, that it is a southern form which occasional!) establishes itself in Long Island Sound. 

 The following are the dimensions in mm. of a specimen of Rliopilema verrillii found by 

 Professor Verrill at Outer Island, near Hranford, Connecticut, in Long Island S<jund, on 

 September 12, 1909. 



Diameter of contracted bell, 218. Width of largest velar lappets, 11. 



Diameter of fully-expanded bell, 268. Length of largest velar lappets, IJ.5. 



Perradial diameter of arm-disk, 155. Length of scapulets, 36. 



Interradial diameter of arm-disk, 76. Length of mouth-bearing part of scapulets, 35, 



Width of each perradial colunm of arm-disk, 33. Length of lower arms, 65. 



Circumferential width of subgenital ostium, 49 Witlth at widest distal part of lower arms, 54±. 



Radial width of subgenital ostium, 27. Width of lower arms at points of origin from arm-disk. 



Width of zone of circular muscles, 54. 26 to 32. 



Width of ocular lappets, 3. Length of longest mouth-arm appendages, 26. 



Length of ocular lappets, 5. 5. 



Genus EUPILEMA Haeckel, 1880. 

 Eupilema, Haeckel, 1880, Syst. der Medusen, p. 590. — Vanhoffen, 1888, Bibliotheca Zoologica, Bd. i, Hi-fi. 3, p. 43. 



The type species is EupJiilcma scapulare Haeckel, from the Malay Archipelago. Cyanea 

 rhizostoma Brandt, 1838, may be of the same genus, but is too imperfectly described to be 

 determined. 



GENERIC CHARACTERS. 



Rhizostoniata scnpidata with 8 free, 3-winged mouth-arms, without filaments, clubs, 

 or other appendages. 16 radial-canals all connected by an anastomosing network ot vessels 

 in the outer parts of the subumbrella. 



This genus is closely related to Rhizostoma, but has no mouth-arm appendages. 



Eupilema scapulare Haeckel. 



Eupilema scapulare, Haeckel, 1880, Syst. der Medusen, pp. 582, 590.— Vanhoffen, i888,Biblio. Zool., Bd. i, Heft. 3, p. 43. 



Bell 150 mm. wide, 50 mm. high, hat-shaped with rounded dome. 8 rhopalia, 14+ lappets. 

 In each octant 8 pairs of long, narrow, rectangular, projecting, velar lappets, between 2 small, 

 oval, ocular lappets. Mouth-arms not quite as long as bell-radius. Scapulets simitar-shaped, 

 as lono- as free, upper part of arm. 17 radial-canals all connected by an anastomosing network 

 of vessels which extend inward to the zone of the bases of the arm-disk pillars. The torm 

 of the scapulets shows that they are only the secondarily separated, uppermost lappets ot the 

 dorsal wings of the mouth-arms. Color (?) Sunda Archipelago, Sumatra. 



Very briefly described from a preserved specimen by Haeckel. 



Genus STOMOLOPHUS L. Agassiz. 



Slomolophus, Agassiz, L., 1862, Cent. Nat. Hist. U. S., vol. 4, pp. 138, 151.-ACASSIZ, A., 1865, North American Acal., p. 40.- 

 Claus, 1883, Organisation und Entwick. Medusen, p. 60.— von Lendenfeld, 1884, Proc. Lmnean Soc. New South W ales, 

 vol. 9, p. 292.— Vanhoffen, 1898, Bibliotheca Zoologica, Bd. i. Heft. 3, pp. 30, 42.— Maas, 1903, Scyphomedusen der 

 Siboga Eiped., Monog. 11, p. 80. 



Brach:olophu!+ Slomolophus, Haeckel, 18S0, Syst. der Medusen, pp. 597, 598. 



The type species is 5. meleagris L. Agassiz, which ranges from South America to the 

 mouth of Chesapeake Bay, United States, and is apparently found also on the Pacific side 

 of the Isthmus of Panama. 



GENERIC CHARACTERS. 



Rhizostomata scapulata with a central mouth-opening. With a well-developed, tube-like 

 manubrium formed by the fusion of the lateral edges of the 8 primitive mouth-arms. Only 

 the extreme ends of the mouth-arms are free and they branch complexly. 8 pairs ot scapulets 

 4 separate invaginated gonads. The central stomach gives rise to 16 radial-canals, which 

 are all connected by a marginal network of anastomosing vessels. 8 marginal sense-organs. 



Brachiolophus Haeckel is only a young stage of Stomolophus. 



