176 Papers from the Department of Marine Biology. 



35 specimens of Atolla were found by the Albatross among the Philippine 

 Islands; and of these 18 are more or less typical A. wyvillei, 4 are intermediate 

 in condition between A. ivyvillei and A. alexandri, 3 are intermediate between 

 A. wyvillei and A. bairdii, 1 combines the characters of A. bairdii, A. gigantea, 

 and A. verrillii, 6 are intermediate, and 3 are A. bairdii forma valdivice. 



The specimen of Atolla gigantea which shows affinities with A. bairdii and 

 A. verrillii was dredged at Station D 5647, from Buton Strait, about 11.6 

 miles off North Island, depth 519 fathoms, bottom green mud. This medusa 

 is a large one, being 130 mm. wide and with 29 tentacles. The diameter of 

 the central lens is about 94 mm. and the thickness of its gelatinous substance 

 21 mm. The margin of the central lens is irregularly notched, but is without 

 distinct radial furrows. Its margin overarches the ring-furrow, which is 15 

 mm. deep. The outer edge of the ring-furrow exhibits an annular ridge, which 

 is, however, overarched and hidden under the projecting margin of the central 

 lens. Two-thirds of the circumference of the peripheral edge of this annular 

 ridge is entire and plain, as in A. bairdii, but about one-third of it is notched, 

 the notches tending to lie in the radii of the tentacular pedalia, as in the 

 typical A. gigantea. 



Other dimensions of this medusa (given in millimeters) are as follows : 

 tentacular pedalia 11.5 long, 10.5 wide; rhopalar pedalia 11.5 long, 8. 5 wide; 

 diameter across subumbrella to outer edge of ring-muscle about 126; width of 

 ring-muscle 7.75; diameter across zone of gonads about 96, each gonad is 

 circular, disk shaped, and about 15 in diameter, the medusa being a female, 

 and apparently nearly mature; diameter across central stomach about 66; 

 length of manubrium 46. 



It thus appears that in this specimen the central lens is more than half as 

 wide as the medusa, as in A. bairdii and A. verrillii; its outer margin being 

 slightly notched as in A . bairdii and A . valdivice. The annular ridge is prob- 

 ably concealed under the overarching edge of the central lens, as in A. wyvillei 

 and A. verrillii. Part of the outer edge of the annular ridge is entire and 

 even, as in A. bairdii and A. valdivice, and part of it is notched and furrowed, 

 as in the typical A . gigantea. 



It is probable that most of the so-called specific distinctions between the 

 various Atoll as are mere individual peculiarities of no greater specific value 

 than the difference between blue eyes and brown in man. 



List of stations among the Philippines from which specimens of Atollas 



allied to A. wyvillei were obtained. 



D 5201, April 10, 1908, from Sogod Bay, Southern Leyte Island, depth 554 fathoms, bottom 



gray sand and mud. 1 typical A. wyvilki with 23 tentacles. Dimensions 



given in table. 

 D 5285, July 20, 1908, about 17.5 miles off Malavatuan Island in the China Sea, depth 



272 fathoms, bottom soft mud. 11 specimens of medium size, not well 



preserved, but all are probably A. wyvillei. 

 D 5348, December 27, 1908, in Palawan Passage, about 33.5 miles from Point Tabonan, 



depth 375 fathoms, bottom coarse sand. 1 specimen too imperfect for 



accurate specific determination. 

 D 5471, June 19, 1909, about 15 miles off Sialat Point Light on the east coast of Luzon, 



depth 568 fathoms. 2 specimens closely allied to A. alexandri, one with 29 



and the other with 26 tentacles. The dimensions of both are given in the 



table. 

 D 5486, July 31, 1909, about 6 miles off Batobolo Point, between Leyte and Mindanao, 



depth 585 fathoms. 4 badly preserved specimens, too imperfect for specific 



determination. 



