ATOLLA WYVILLEI. 



39 



Two other species, A. gigantea and A. alexandri, described by Maas ('97) 

 from alcoholic specimens, seem to me rather problematical. A. alexandri, it is 

 true, has since been recorded by Agassiz and Mayer (: 02) and by Mayer (: 06) 

 from the Pacific ; but examination of the three specimens on which these 

 two records were based has shown that, instead of having the extremely 

 broad central disc characteristic of A. alexandri (Maas, '97, : 03, p. 16), their 

 proportions agree with those of the present series ; and that they all show 

 broad radial furrows, for which reasons they must be referred to A. wyvillei, 

 not to A. alexandri. 



The specimens taken during the expedition of the " Albatross" to the 

 Eastern Pacific are all of one species, which I have identified as A. wyvillei on 

 account of the form of the radial furrows of the central disc. 



Atolla wyvillei Haeckel. 



AtoUa wyvillei Haeckel, '80, p. 488; '82, p. 113, pi. 29, figs. 1-9; Vanhofeen, : 02% p. 13, 



taf. 5, fig. 22; Browne, : 08, p. 241. 



Plate 8, Fig. 1 ; Plate 9, Fig. 3 ; Plate 10, Figs. 8, 9. 



In addition there have been available nine other specimens, previously 

 collected by the "Albatross" at various localities in the Eastern Pacific 

 including the Hawaiian Islands and coast of Southern California. All of 

 them show radial furrows more or less clearly. 



In the largest specimen, 95 mm. in total diameter, the only visible traces 

 of furrows are very slight notches on the margin of the disc. In somewhat 

 smaller specimens, particularly in the remarkably well-preserved individual 

 with the disc 55 mm. in diameter, from Station 4645, the furrows, restricted 

 to the marginal region of the disc, show exactly the condition figured by 



