566 



MEDUS/E OF THE WORLD. 



Atolla chuni Vanhoffen. 



Atolla chuni, VANHOFFEN, 1902, Wissen. Ergeb. doutsch. Tiefsee Expedition, Dampfer Paldivia, Bd. 3, Lief. I, p. 12, taf. I, 

 figs, i, 2; taf. 5, fig. 26. BROWNE, 1908, Trans. Roy. Soc. Edinburgh, vol. 46, p. 240. 



Bell 27 to 50 mm. wide, 9 to 15 mm. high. Central lenticular disk 14 to 27.5 mm. wide 

 with 23 faint radial furrows at the margin. Annular furrow 0.5 to 1.75 mm. wide. Zone 

 of pedalia 2.25 to 3.5 mm. wide. 24 tentacles. Species distinguished by 7 to 9 small, pearl- 

 colored, papilla-like protuberances over the exumbrella surfaces of each marginal lappet; 

 commonly with one papilla in the center and the others in two lateral rows. 2 specimens found 

 by the I'alJivia off Cape of Good Hope, Africa, November 1 8, 1898; and I by the Scot- 

 tish Antarctic Expedition, in a trawl at 1,332 fathoms, in the same region. 



359 



FIG. 359. Atolla gigantea, after Maas, in Mem. Mus. of Comp. Zool. at Harvard College. 



Fi<;. }6o. Atolla chuni, after Vanhoffen in I'aldivia Expedition. 



FIG. 361. Atolla wyvillc I, 0.75 natural size, drawn by the author, from a specimen in the National Museum, Washington. 



Atolla wyvillei Haeckel. 



, , , .., 



Atolla alexanJri, MAAS, 1897, Mem. Museum C 

 A 

 U 



ss acs, AECKEL, 10, oc.c., p. 49. 



exanJri, MAAS, 1897, Mem. Museum Comp. Zool. at Harvard College, vol. 23, p. 81, taf. 1 1, fig. 2; taf. 14, figs. 4, 5. 

 GASSIZ, A., and MAYER, 1902, Mem. Museum Comp. Zool. at Harvard College, vol. 26, p. 156. MAYER, 1906, Bull. 

 . S. Fish Commission, vol. 23, p. 1138, plate 2, fig. 7; plate 3, figs. 10, u. 



This species is characterized by the numerous, wide, radial notches or furrows in the 

 margin of the central lens of the exumbrella. These are much wider and deeper than in A . 

 verrillii. Exumbrella surface of lappets smooth, not beset with papillae as in A . chuni. This 

 medusa is probably identical with Collaspis achillis Haeckel, but in the latter the furrows of 

 the central lens are represented as deep, narrow clefts, whereas in A.iL'yvillci they are shallow 

 notches which vary greatly in prominence in individual medusae. Moreover, in A. wyvillei 

 the pedalia are short and broad, while in A . achillis they are long and narrow. The central 

 lens and the pedalia are separated only by a ring-furrow and there is no prominent ridge periph- 

 eral to the ring-furrow such as is seen in A. bairdii. The medusa becomes 73 mm. wide and 

 there are usually about 22 to 28 tentacles. The bell is flatter than a hemisphere. Found in the 

 Antarctic and Southern Atlantic and Pacific. The Albatross obtained it in the Philippine 

 Islands, tropical Paci-fic. 



