STEPHAxNTOMIA AMPHITRIDIS. 287 



Stephanomia amphitridis Peron and Lesueur. 

 Plate 18, figs. 1-8. 



Slephnuomia amphitridis P£ron and Lesueur, '07, pi. 29, fig. 5; Huxley, '59, p. 72, pi. 6; Schneider, 



'98, p. 118. 

 ? Stephanomia foliacea QuoY and Gaimakd, '34, p. 74, pi. 3, fig. '8-12. 

 Stepha7wmia amphitritis L. Agassiz, '62, p. 368. 

 ? Stephanomia nereidum Haeckel, '88a, p. 40; '88b, p. 221. 

 Phyllophysa sguamacea Haeckel, '88a, p. 40; '88b, p. 225. 

 Cupulita amphitritis Bedot, '96, p. 408. 

 Stephanomia .sp., Lens and Van Riemsdijk, : 08, p. 84, pi. 15, fig. 113-114. 



Station 4704 surface 1 .segment of the siphosome 95 mm. 



long, with 7 siphons (Plate 18, 



fig. 1). 

 " 4705 .300 fathoms to surface 6 segments of the siphosome, 20- 



30 mm. long. The material is 

 all in beautiful condition. 



The original figure of this species by Peron and Lesueur ('07), though 

 sufficient for identification, shows only the general external aspect of the 

 siphosome and the fact that the tentilla have a single terminal filament. 



Our only knowledge of the structure of this interesting Siphonophore is 

 contained in the accounts by Huxley ('59) and by Haeckel ('88). Fortunately 

 the present material is well preserved, though only the siphosome was taken. 



The nectosome has been seen by Haeckel alone, who states ('88b, p. 221, 

 "Stephanomia nereidum") that "the biserial nectosome composed of twelve 

 complete nectophores had nearly the same form as that of Crystallodes txitrea." 

 But since his S. nereidum has never been described in detail, or figured, its iden- 

 tity with S. amphitridis must remain doubtful. Bedot classes it under the 

 heading "especes incompletement connues" ('96, p. 411). Schneider, without 

 discussing nereidum, suggests that amphitridis may actually lack a nectosome. 

 But when we consider how seldom the species has been taken, the strong proba- 

 bility that Haeckel's species was identical, and the fact that no other Physophore 

 lacks a pneumatophore, even if nectophores be wanting, we must conclude that 

 such a supposition is most improbable. 



Siphosome. The stem is stiff and but slightly contractile. The bracts form 

 a stout cylindrical carapace, although they are less regularly arranged than 

 Huxley supposed. They lie arranged in four or five irregular somewhat diagonal 

 rows, instead of in four rows, as he describes them. Furthermore, their external 

 location does not necessarily indicate the level at which their supporting lamellae 



