51 IS 



MEDUSAE OF THE WORLD. 



Atorella subglobosa Vanhbffen. 



Atorella subglobosa, VANHOFFEN, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Valdivia, Bd. 3, Lfg. i, p. 33,taf. 3, fig. u. 

 MAAS, 1903, Scyphomedusen der Siboga Expcd., Monog. 1 1, p. 10, taf. 3, fign. 16-18. Bigelow, H. B., 1909, Mem. Mus. 

 Comp. Zool. at Harvard College, vol. 37, p. 30. 



Bell globular, 15 to 17 mm. in diameter. 6 mainly solid, tapering tentacles, about as long 

 as the bell-radius. 6 marginal sense-clubs, each with a terminal mass of concretionary 

 crystals, arise from very shallow niches in bell-margin. There are 12 wide, shallow, slighty 

 cleft marginal lappets. Ring-furrow on exumbrella not very deep. Central diskofexum- 

 brella more than twice as wide as zone of pedalia. The 12 pedalia alternate with the lappets 

 and are separated one from another by shallow furrows. Throat tube 4-sided, mouth cruci- 

 form. There are 4 clusters of gastric filaments, each cluster consisting of about 20 filaments. 

 The ring-sinus gives rise to 12 pouches in the radii of the tentacles and sense-organs and there 

 is a marginal ring-canal as in A folia or Pertphylla. 4 interradial, sac-like, swollen gonads 



arise from floor of subumbrella beyond the zone of the 

 gastric filaments. Muscular system of subumbrella quite 

 similar to that of Nattsithoe, but the ring-muscle is very 

 poorly developed. 



Stomach and gastric filaments brown, gonads yel- 

 lowish-brown. Subumbrella muscles white, all other 

 parts translucent. 



VanhofFen describes a specimen from Dar es 

 Salaam, east coast of Africa, and Maas describes 

 another from the Malay Archipelago. Our description 

 is derived mainly from that of Mass, his specimen being 

 the more perfect. Vanhoffen's figure shows 6 gonads. 



Atorella vanhoffeni Bigelow. 



FIG. 362. Atorelia subglobosa, after Maas in 

 Siboga Expedition. 



Atorella ranhofltni, BIGELOW, H. B., 1909, Mem. Museum Comp. Zool. at 

 Harvard College, vol. 37, p. 30, plates i, u, and n. 



Bigelow had three specimens. In two of these the 

 bell was 5 mm. high and 6 mm. wide, and one was 3 mm. high and 7 mm. in diameter. The 

 ring furrow is a deep cleft. The entire exumbrella surface is besprinkled with wart-like, nema- 

 tocyst-bearing prominences, thus being very different from the smooth surface of the bell of 

 Atorella subglobosa. The 6 tentacles are each about as long as the bell-diameter. They taper 

 outwardly but each terminates in a knob-like tip, instead ot having simple, pointed ends as 

 in A. subglobosa. The 6 rhopalia closely resemble those of Atolla, but the exumbrella surface 

 of its covering scale is covered with thickened ectoderm, not with a thin layer as in Atolla. 

 There is a large lithocyst and ventral bulb, but no ocellus. There are 12 long, oval, marginal 



FIG. 363. Alorella vanhofleni, after H. B. Bigelow, in Mem. Mus. Comp. Zool. at Harvard College, 1909. 



