ATLANT. DEEP-SEA EXPED. 1910. VOL. 



HYDROIDA. 



cladium, which is a direct continuation of the free anterior 

 wall of the hydrotheca. A perforation of the anterior 

 wall was not observed between the hydrotheca and the 

 adnate portion of the mesial nematophore. 



The construction of the adnate part of the thecal wall 

 of this species closely resembles that of Thecocarpus 

 myriophyllum (Lin.), and it is possible that we shall be 

 obliged to place it in the genus Thecocarpus. On the 

 other hand, the origin and arrangement of the nemato- 

 thecae of the stem closely correspond to what Allman 1 ) 

 has described in Cladocarpus dolichotheca Allman and 

 Cladocarpus ventricosus Allman. I have therefore provi- 

 sionally placed the species in the genus Cladocarpus. 



Gratnmari a Stimpson. 

 Gramtnaria conferta (Allman). 



West of Gibraltar (Stat. 23) two small sterile colonies 

 from 1215 metres. 



The upper parts of the colonies are monosiphonic, 

 but the lower parts have accessory tubes, and thus we 

 have a typical Grammarla with erect colonies. 



The hydrothecae have no diaphragm. Their proximal 

 parts are adnate to the tubes, and, indeed, the only dif- 

 ference from the species of Filellum is that the hydro- 

 ihecae in the latter are more distinctly constricted where 

 they join the stolons. This constriction is, however, indi- 

 cated in Gramtnaria confeita too. 



Gramtnaria (Filellum) serpens (Hassall). 



Near Cape Bojador (Stat. 37) a few hydrothecae 

 growing on an alga from 39 metres. At the southern 

 edge of the Newfoundland bank (Stat. 70), a few hydro- 

 thecae growing on fragments of the axis of a gorgonid 

 from 1100 metres. 



Kramp 2 ) refers this species to the genus Lafoea, 

 pointing out that "the decumbent, growing part of the 

 hydrotheca may be so short as to cause a great similarity 

 with Lafoea dumosa, and that the stem is creeping or 

 nearly always so, is an insufficient generic character, 

 especially among these forms where the erect stem is a 

 rhizocaulus. Through Lafoea dumosa, Filellum serpens 

 is so closely related to the genus Lafoea, that it should 

 be included in the latter." But the similarity with Lafoea 

 dumosa (Flem) is only a superficial one. Where the 

 hydrotheca of Giammaria (or Filellum) is adnate to the 



tube, no difference can be traced between the wall of the 

 tube and that of the hydrotheca; they are in fact no more 

 separable than they are in Sertulariids or Aglaopheniids. 

 This character distinguishes Grammarla from the closely 

 related genus Lafoea, and therefore we cannot consider 

 them as one genus. 



Sertularella Gray. 



Sertularella cylindritheca (Allman), Hartlaub. 



Near Cape Bojador (Stat. 37) some sterile colonies 

 growing on Nemerlesla Hartlaubl from 39 metres. 



Sertularia (Lin.). 

 Sertularia distans 



amouroux. 



South of the Azores (Stat. 51) many sterile colonies 

 on floating sea-weed; Sargasso sea (Stat. 67) abundant 

 with gonangia on floating sea-weed. 



Diphasla (L. Agassiz). 



Diphasia pinaster (Ellis and Solander) Hincks. 



West of Gibraltar (Stat. 20) in 141 metres, several 

 large fertile colonies. 



Diphasia attenuta Hincks(?) 



A fragment of a robust colony from 39 metres near 

 Cape Bojador (Stat. 37), seems to belong to this species. 



THECAPHORA PROBOSCOIDEA. 



Campatmlaria (Lamarck). 



In this genus we must include some species of Eu- 

 copella. The diagnosis of the latter is as follows: "Die 

 Polypenstocke bestehen aus einer Hydrorhiza, von welcher 

 unverzweigte Hydrocauli abgehen. Die Nahrpolypen wer- 

 den von becherformigen Hydrotheken umschlossen. Die 

 Medusen sprossen an verzweigten Polyposlylen." 3 ) In 

 this diagnosis I can see no difference from the general 

 features of the Clytla-group, like Campanularia Johnstonl 

 Alder. On the other hand Hartlaub 4 ) points out that 

 the form of the hydrotheca "keineswegs immer becher- 

 formig ist, sondern nach von Lendenfeld's eignen Abbil- 

 dungen, vor allem aber nach Bale ausserordentlich variirt 



') Report on the hydroida collected during the exploration of the Gulf Stream (Mem. Mus. Comp. Zool., vol. V) Cambridge, 

 Mass. 1877, pp. 50—52. 



"-) Report on the hydroids. (Danmark Expeditionen til Granlands Nordestkyst 1906 — 1908, Bd. V). Kjabenhavn 1911, p. 373. 



3 ) VON Lendenfeld: Ueber Coelenteraten der Siidsee (Zeitschr. wiss. Zool., Bd. 41) 1885, p. 658. 



4 ) Die Hydroiden der magalhaensischen Region und chilenischen Kiiste (Zool. Jahrb. Supplement V, Plate, Fauna Chilensis, Bd. III). 

 Jena 1905, p. 568. 



