SEMAEOSTOMK^ — UNDOSA, DirLUI^MAUIS. 



609 



Undosa undulata Haeckel. 



Vniiosti undultitii, Hafckkl, 1880, Syst. der MrHust-n, p. 546, taf. ^-^j fign. 5, 6. 



Bell 120 mm. wide, 40 mm. high, flatly rounded. A brown, 16-rayed, star-like figure on 

 exumbrella composed of pigmented nettling ridges. 48 (6X8) sharp-pointed, oval lappets, 

 somewhat longer than wide and projecting prominently; the 16 ocular lappets are somewhat 

 longer than the others. Of the 40 tentacles, the 8 adradial are 2 to 3 times as long as bell- 

 radius, twice as long as the 16 secondary, and 3 times as long as the 16 tertiary tentacles. 

 All tentacles are hollow. The 4 mouth-arms resemble those of Aitrcllia aurita, but their 

 margins are more curtain-like and more folded and provided with numerous tentacular 

 filaments. The 4 gutters of the mouth-arms are very deep. The 4 folded, interradial, bag- 

 like gonads project from the floor of the subumbrella. There are no subgcnital ostia. The 

 genital radius is about halt that of the bell itself. Margin of central stomach circular. 8 

 simple, unbranched, adradial canals and 8 (perradial and interradial) canals, which give 

 rise to numerous side branches which in turn anastomose, forming a network of vessels con- 

 nectins: all 16 canals one with another and with the marginal rinij-canal. 



The general color is bluish, and 

 the star-like marking on the exum- 

 brella dark-brown. Found at Fer- 

 nando Po, coast of Guinea, Africa. 

 Haeckel's " Ulnians prototypiis" 

 from St. Helena is probably the 

 young of this species (loc. cit., 1880, 

 P- 545. taf. 33, fign. 1-4). 



Genus DIPLULMARIS MAAS, 1908. 



Diplulmarii, Maas, 1908, Expedition Anlarctique 

 Fran^aise, Meduses, p. 9. 



Vlmaropsis, Vanhoffen, 1908, Deutsche .Siidpolar 

 Expedition, Bd. 10, Zool. 2, p. 45. 



The type species is Dipliilmans 

 antarcttca, Maas, 1 908, from the 

 Antarctic Ocean. 



GENERIC CHARACTERS. 



Ulmaridas with i6 tentacles, 64 

 marginal lappets, and 16 marginal 

 sense-organs. 16 branched radial- 

 canals in the radii ot the sense-organs 

 and 16 simple straight radial-canals 



in the tentacular radii. All 32 of the canals are joined by an anastomosing network of vessels 



near the bell-ma rtrin. 



Fic. ,89. — L rulosa uttdulatn, after HatLkel is Das S)st. dcr Medusen. 



This medusa bears the same relation to UiiJo.ui that Sanderia does to Dactylomctra. 

 Indeed, there is a remarkable case of parallelism of mutation in the Pelagidae and Ulmaridae 

 as is shown in the accompanying table. 



Diplulmaris is a connecting link between the subfamilies UmhrosiJii, in which the ten- 

 tacles arise from clefts between the lappets, and Sthenonidii, in which they arise from the 

 subumbrella floor; for in the young Diplulmaris the tentacles arise from the subumbrella. 



