IOO 



HYDROIDA II 



Sertularella amphorifera Allman. 



1877 Sertularella amphorifera, Allman, Hydroida of the Gulf Stream, p. 22, pi. 15, figs. 8 — 10. 



1912 Sertularella amphorina, Bedot, Materiaux pour servir a Thistoire des Hydroides, 4™ periode, p. 352. 



Upright slender colonies with monosiphonic hydroeaulus. Stem and main branches slightly 

 prominent. The basal part of the stem is straight, irregularly segmented, without hydrotheca; and 

 branches; higher up, it becomes regularly segmented, like the branches, with a hydrotheca on the 

 distal part of each internodium. The branches arise in irregular alternation, and may themselves 

 again ramify; like the hydrotheca-bearing part of the main stem, they are bent zigzag fashion. The 

 hydrotheca; are large, cylindrical, slightly curved, 

 with three equal sized, markedly prominent 

 teeth, and in the sinuses between them three 

 large triangular lid plates. The hydrotheca is 

 attached to the branch by a narrow base. The 

 polyp has a distinctly prominent abcauliue 

 blind sack. 



The gonothecte proceed from below the 

 base of the hydrotheca;. They are a slender oval 

 to pear-shaped, with a distally central narrow 

 neck, and distinct transverse furrows; the neck 

 passes evenly over into the gonotheca. 



Material : 



I. 111. Sertularella amphorifera 

 from "Ingolf" St. 54. 

 Part of a branch (>( 20). 

 3theca of the stem with the basis 

 of a branch (X 40). 



"Ingolf St. 7, 63°i3' N - , I5°4i' W.; depth 600 fathoms, 4,5° 

 - 54) 6 3 °o8' N, i 5 4 o' W.; - 691 3,9° 



Nutting (1904 p. 88) who had only some fragments of Airman's type specimen to work on, 

 states that Sertularella amphorifera has possibly four hydrothecal teeth, and he gives some drawings 

 where four such teeth are markedly in evidence, as if his specimen had been intact, and not, as he 

 himself expressly notes in the text, defective. Billard (1906 p. 183) on the other hand, reports the 

 species as distinctly tridentate, and this is also plainly to be seen from my specimens (fig. LIU). Be- 

 tween two branches on the stem, the number of hydrotheca; varies from two to five. 



Sertularella amphorifera is evidently very closely related to Sertularella tricuspidata, extreme 

 variants of which may present a strong resemblance to the former. On the whole however, Sertula- 

 rella amphorifera seems to be of considerably more open growth, while its finer structure and long, 

 slender internodia, together with the strongly projecting hydrothecse, give it a typically different 

 appearance from Sertularella tricuspidata, as is apparent at the first glance. 



The finding of Sertularella amphorifera so far to the north is highly interesting. It was pre- 

 viously known only from the sea off Florida at Double Headed Shot Key, 471 fathoms, and from the 

 west coast of Africa, where it was taken at 882 metres' depth. The species thus belongs to the warmer 

 parts of the Atlantic abyssal region, and moves up, in the warm, deep water layers, to the deep off 

 the south-east coast of Iceland. 



