AEGINA CITREA. 73 



brief account agrees closely with figures given by Mayer of young Aeglna 

 rhodina (: 04, pi. 4, fig. 28), it is safe to identify it with that species. It is 

 probable that the same is true of Solmundus tetralinus. 



Aegina citrea Eschscholtz. 



Aegina citrea Eschscholtz, '29, p. 113, taf. 10, tig. 3; Haeckel, '79, p. 338; Maas, : 05, 



p. 71, taf. 11, fig. 72, taf. 13, figs. 79-82. 

 Aegina rosea Eschscholtz, '29, p. 115, taf. 11, fig. 4 ! Haeckel, '79, p. 338. 



Plate 1, Fig. 5; Plate 14, Fig. 5. 



Station 4663 ; 300 fathoms to surface ; one fragmentary specimen, 6 mm. 

 in diameter. 



Station 4672 ; bottom of Tanner net, 400 fathoms ; one specimen, very 

 fragmentary, about 15 mm. in diameter. 



Station 4717 ; 300 fathoms to surface ; one poor specimen, 12 mm. in 

 diameter. 



Station 4719 ; 300 fathoms to surface ; one specimen, 20 mm. in diameter. 

 This is the specimen photographed (PL 1, fig. 5) and from which the colored 

 figure (PI. 14, fig. 5) was drawn from life. 



Although I have four specimens of Aegina citrea at hand, I am not in 

 much better position to give a satisfactory diagnosis of the species than 

 was Maas (: 05). His suggestion that the secondary subdivision of the eight 

 main gastric pockets into sixteen minor lobes may prove to separate the 

 Pacific from the Atlantic species is borne out by the fact that this feature 

 appears in the two larger specimens in the present collection, as is shown in 

 the photograph (PI. 1, fig. 5). It seems probable that the number of otocysta 

 may likewise prove to be of specific importance. Haeckel (79) records six- 

 teen (four per quadrant) for A. rhodina; and since he found the same number 

 in A. canariensis, which is certainly nothing but a young stage of the latter, 

 this number may be taken as characteristic of that species. In A. citrea, on 

 the other hand, Maas (: 05) could distinguish only eight ; while I find two per 

 lappet, in every case in which the margin is in good enough condition to 

 allow of counting. Maas has suggested, though without actual evidence, thai 

 there may be secondary tentacles such as are present in Aeginura, as well as 

 otocysts on the margin in this genus; but I find no indications of these 

 structures in the present specimens. 



