AGALMA. 275 



characters, and in consequence groups A. okeni with A. eschscholtzi Haeckel, 

 from which it is easily distinguished by the outhnes of these organs as well as 

 by other minor features. The fragments described by Quoy and Gaimard ('34) 

 as Stephanomia triangularis, S. alveolata, and S. heptacantha probably belong 

 here. At any rate there is nothing in their figures to suggest that they were 

 dealing with more than one species, while the form both of bracts, and of necto- 

 phores, and the tricornuate tenillae agree very well with A. okeni. 



The Agahnid siphosome which Lesson ('26) combined with Abylopsis tetra- 

 gona (p. 225) under the name Plethosoma crystalloides, likewise suggests ^4. okeni. 

 Schneider has identified with A. okeni the detached nectophores described by 

 Eysenhardt ('21a, p. 369) as Cuneolaria incisa. But the only ground for this 

 is the supposition that the nectophores in question were identical with the frag- 

 ment described and figured by Chamisso and Eysenhardt ('21) as Stephanomia 

 amphitritis. The latter, it is true, probably does belong to A. okeni, but in 

 view of the facts that the incisa nectophore was neither figured, nor described, 

 that Chamisso and Eysenhardt themselves disagreed as to its identity with their 

 "Stephanomia amphitritis," and that it might equally well belong to any Agalma, 

 or even to a Stephanomia, it is useless to identify it with A . okeni. 



Agalma pourtalesii Agassiz and Mayer ('99) resembles A. okeni in the thick- 

 ness of its bracts and in their prismatic form, as well as in general habitus. It is 

 true that Mayer ( : 00) has described its tentilla as without involucre, although 

 tricornuate. But Dr. Mayer himself informs me that later studies have shown 

 that an involucre is present, and he has very kindlj- shown me drawings in which 

 this character appears. Furthermore, the probable type of pourtalesii (now 

 in the collection of the Museum of Comparative Zoology) differs in no way from 

 A. okeni, so far as its rather vuisatisfactory preservation allows me to judge. 

 For these reasons there is every justification for uniting it with the latter species. 



Lens and Van Riemsdijk have described the Agalmas ("Crystallomias") 

 of the "Siboga" expedition, all of which are of the general okeni type, under 

 two headings, " Crystallomia Spec. Group I."; and "C. Spec. Group IL," 

 separating them by the structure of the tentilla. The excellent condition of 

 the present series of A. okeni has allowed me to make a careful test of the sup- 

 posed divergences, and since the tentilla are described below (p. 280) in detail, 

 it will suffice here to state that the differences between them are all evidences 

 either of different stages in growth, or of individual variation. 



The second well-known Agalma was first described by Sars ('46), who 

 combined it with a Stephanomia usually known as Cupulita picta, under the 



