SCYPHOMEDUSAE COLLECTED BY STEAMER " ALBATROSS.' ' 195 



living or freshly preserved animals, and am inclined to believe that the 

 delicate membrane separating adjacent pouches was broken in Van- 

 hoffen's specimens, which had been preserved for a long time in 

 formalin. Moreover. Vanhoffen found that in some of the Atlantic 

 medusae from the Bahama-Florida region the subumbrella warts are 

 arranged as in L. aquila of the Pacific. It thus appears that the 

 Pacific form is at best only a variety of the Atlantic species, and both 

 should be called Linuche unguiculata. 



Prof. E. G. Conklin in 1908 1 described the swarming habits, struc- 

 ture of the egg, and the segmentation in this medusa. The eggs are 

 laid at 8 o'clock in the morning, after which the medusa sinks and 

 soon dies. The segmentation is nearly equal and synchronous. The 

 peripheral layer of ooplasm of the egg becomes the peripheral layer 

 of the gastrula and gives rise to the cilia of the ectoderm. The inter- 

 mediate layer gives rise to the principal part of all the cells of the 

 gastrula, while the central part of the egg is the precursor of the 

 cleavage cavity and serves as a kind of a fluid yolk for the nourish- 

 ment of the surrounding cells. 



Genus ATOLL A Haeckel, 1880, sensu Fewkes. 



Atolla Haeckel, 1880, Syst. der Medusen, p. 488. — Fewkes, 1886, Report 

 Commissioner of Fish and Fisheries of U. S. for 1884, p. 934. — Mayer, 

 1910, Medusae of the World, vol. 3, p. 561.— Bkowne, 1910, National 

 Antarctic Expedition, Nat. Hist., vol. 5, Coelenterata, V. Medusae, p. 47. 



Generic characters. — Coronatae with numerous (nine or more) ten- 

 tacles and equally numerous marginal sense organs. Twice as many 

 marginal lappets as sense organs. Eight adradial gonads and four 

 interradial subgenital ostia. Four lips. The tentacles and marginal 

 sense organs alternate regularly, but the insertions of the tentacles 

 and their pedalia are higher up on the sides of the exumbrella than 

 are the insertions of the pedalia of the sense organs. 



The Albatross collection serves to show that A. wyvillei and A. 

 bairdii are closely related if not mere extremes of an intergrading 

 series of one and the same species. For example, two specimens 

 from station D. 5652 in the Gulf of Boni, depth of 525 fathoms, have 

 the margin of the central lens distinctly notched with radial fur- 

 rows as in the typical A. wyvillei; but there is an annular ridge 

 on the outer side of the ring-furrow with a plain peripheral margin 

 as in A. bairdii. Also several other specimens show such very slight 

 notches in the margin of the central lens that if one were not look- 

 ing carefully for this feature it would surely pass unobserved and 

 the medusa would be called A. alexandri. A large specimen of A. 

 giyantea, from a depth of 519 fathoms in Buton Strait, shows affini- 



1 Papers from the Tortugas Laboratory of the Carnegie Institution of Washington, 

 vol. 2, p. 155. 



