CORONATvE ATOLLA. 



567 



I am inclined to believe that A. uTcill,-i, A. verrillii, A . alexandri, and A. achillis are only 

 varieties of one and the same species. "A. <ih-\<inJri" is a form of A . wyvillei with indistinct 

 notches in the margin of its central lens. 



A specimen was dredged In the Albatross on April 10, 1908, dredging station No. 5201, 

 off the south end of Levi Island, Philippine Islands, from a depth of 554 fathoms. A side 

 view is shown in fig. ^>i. There were i^ pedalia and tentacles, and 22 radial furrows in the 

 margin of the central disk. The dimensions in millimeters are as follows: 



Diameter of bell 55 



Thickness of bell 26 



Diameter of central lens 40 



Depth of coronal furrow ; 



Length of tentacular pedalia. ... 6.5 Diameter to outer edge of ring- 

 muscle 48 



\\ nlili "f tentacular pedalia 6 \Vidthofring-muscle 3 



Length of pedalia of lappets 6.5 Diauictcr across zone of gonads.. 28.5 



\Vi,ith of pedalia of lappets 



Length of tentacles i ; 



Diameter of manubrium 



I .- M ;ih of manubrium 22 



< ii.ti.i U 7 long in the circumferential direc- 

 tion, 5 wide in the radial direction. 



Atolla wyvillei forma verrillii Verrill. 



Ata/la rrrrillii. VtRRiiL, 1885, Report I'minni- . I'i li .in. I fisheries V. S. A. for 1883. p. ^14. -KiwKis. 1885, Report Commiss. 

 l'ih .in.! l-'i.-herie, 1 - v \.toi iXX-,. p. l'i''; ftiW., 1886, Report for 1884, p. 939, plates 4, 5, 4 figs.; /'-/</., 1889, Report 

 for 1886, p. 530; 1888, American J.iurn. Su., MT. 3, \.il. 3;, p. 1^2; 1888, Ann. .Mag. Nat. Hist., ser. 6, vol. i, p. 253. 

 M*\s. I*T. Mem. Mil emu (."ON i p. /."!. at H.ir. .u,l College, vol. 25, p. 79. VAN MC 1 1 1 1 i \. 1902, Wissen. Ergeb. deutsch. 

 Tiefsee Evped.. I'alJi-ia, Bd. 3, Lief. I, p. 10, taf. 5, fit;. 23; taf. 6, fig. 39; taf. 7; 1908, dcutsche Sudpolar Expedi- 

 tion, Bd. 10, Zool. 2, p. 311. 



This form is distinguished from the typical Atolla hnirJii and resembles A. wyvillei by the 

 absence of a projecting annular ridge on the outer side of the ring-furrow, the numerous, 

 fine, radial furrows of its central dome, the long, narrow pedalia of the sense-organs, and the 

 smallness of its marginal lappets. The medusa becomes 95 mm. wide and has between 14 to 28, 

 usually 22, tentacles and marginal sense-organs and 28 to 56 small lappets. Central lens of 

 exumbrella wider than in ,/. Inui-iln. It is found in deep water in the Atlantic, Indian, and 

 Pacific Oceans. Most of the specimens have been obtained in open nets dragged from depths 

 of 373 to 2,369 fathoms; but several hare been found upon the surface. It is probably only 

 a variety of//. wyvilLi. 



Family ATORELLID^C Vanhoffen, 1902. 



AtorelliJic, YANHOITKN, 1902, \Vissen. Ergeb. deutsrh. Tiefsee Expedition I'ltlili: ia, Bd. 3, I,fg. I, p. 51. BIGELOW, H. B., 1909, 

 Mem. Museum Comp. Zool. at Harvard College, vol. 37, pp. 21, 30. 



FAMILY CHARACTERS. 



with 6 rhopalia. 



There is hut a single known genus, this being .Itor.-lla. 



The relationship between the Atorelluhe and other Corona t;c is unknown; tor in the 

 Periphyllidae, Paraphyllinidae, and Ephyopsidae there are 4 or 8 rhopalia, and in the Collaspidae 

 a large (more than 8) but indefinite number ot these organs; and it is impossible at present to 

 determine how the number h may have been derived in the Atoiellidx. It is probable, how- 

 ever, that its affinities are much closer to Atolla than to the other Coronatae. 



Genus ATORELLA Vanhbffen, 1902. 



Aiorella, VANHOFFEN, 1902, \\ 'i^en. Ergcb. deutsch. Ticfsce Expedition, Dampfer Vald'rvia, Bd. 3, Lfg. i, p. 33. MAAS, 1903, 

 Scyphomedusen der Sihoga Expedition, Monog. 1 1, p. 10. BIGELOW, H. B., 1909, Mem. Museum Comp. Zool. at Harvard 

 College, vol. 37, p. 30. 



The type species is Atorella sukglobosa Vanhoffen, of Dar es Salaam, Africa, and from 

 the Malay Archipelago. 



GENERIC CHARACTERS. 



Coronatae with 6 marginal sense-organs, 6 tentacles, 12 marginal lappets, and 12 pedalia. 

 A coronal furrow is present, and the 12 pedalia alternate with the lappets. There is a poorly 

 developed ring-muscle in the subumbrella. 4 lips, 4 interradial gonads. 



