S6 



HYDROIDA II 



Material: 



"Ingolf St. 25 63°3o' N., 54°25' W., depth 582 fathoms 3,3° 



- - 29 65°34' N., 54°3i' W, - 68 - 0,2° 



- - 34 65=17' N, 54°i7' W., - 55 - 



- - 93 64^24' N, 35°i4' W, - 767 - i>46° 



- - 97 65°28' N., 27°39' W, - 45° - 5,5° 



- - 127 66°33' N., 20°05' W., - 44 - 5,6° 



Greenland: Davis vStrait, depth 80 fathoms (withont further details) [type specimen of Clado- 



carpiis crf)nilaf!is\ 

 65°39' N., 28°25' W., depth 553 fathoms [type specimen of Cladocarpus crcnulatiis\. 



CladocarpHs forniosns is described in detail by Ritchie (1909) from some colonies taken at 

 about the same place as A 11 man's type specimens. Among the features which he here notes is 

 the fact that the opening margin of the sarcotheca; is "serrate". Most of the present colonies fully 

 agree with Ritchie's careful description. We have, however, from the "Ingolf St. 25, in addition 

 to many typical colonies, also some few of slightly different structure (fig. XLV). The hydrothecse 

 are here somewhat broader than the normal, the septum is set a little deeper down, and goes consider- 

 ably fartlier in towards the adcladial side than in ordinary colonies of the species, while on the other 

 hand the internodial jibs are less pronotmced, and fewer in number. Furthermore, all the sarcothecce 

 here have smooth opening margin. Tlie points of difference, as compared with the typical form of 

 Cladocarpus /orMos2is,s.re thus sufficiently marked; they are however, too slight to warrant our mark- 

 ing off a distinct species, since no other differences can be discerned. The colonies should thus merely 

 be regarded as representatives of a special variety within the species. 



Ritchie (1909 p. 314) points out that Levinsen's Cladocarpus creiiulalus (1893 p. 68) must 

 be regarded as a synonym of Cladocarpus forvios2is\ and after having examined Levinsen's type 

 specimens, I must entirely concur in this view. Bonne vie (1899 p. 95) mentions Aglaophcnia formosa 

 from a station near Si^itzbergen ; lier description however, differs not a little from Allman's, and 

 from those of later writers; in the first place, no mention is made of the intrathecal septum, in addi- 

 tion lo whicli, the description of the hydrotheca as "almost cylindrical, regularly dentated round the 

 margin" is luirdly in accordance with what we otherwise know of the species; the published drawings 

 (1898 Taf. 2, fig. 3) also differ somewhat, so that the identity of the colony seems doubtful. An investi- 

 gation of the type specimen, however, shows that the intrathecal septum is present, and that the spe- 

 cimen only differs from the colonies here in question in the somewhat more distinct and regular den- 

 tition of tlie hydrotheca margin. In addition, one of the phylactogonia is piiniately branched, as in 

 Cladocarpus paradiseus Allman, while the others are dichotomically branched. 



Cladocarpus formosus is plainly one of the most common forms in the warmer tracts belonging 

 to the upper part of the abyssal region in the North Atlantic (fig. XLVI) and penetrates thence up 

 into the lower part of the littoral region. It is originally known from the southernmost part of the 

 cold area, where the latter runs into the Faroe Channel, but should here be regarded as a visitor, 

 brought in by larval transport with the Atlantic current. The species is previously known from 



