HYDROIDA II 89 



Cladocaf pus Diana exhibits also certain peculiarities in the gonosome (fig. XLVII a). The phyl- 

 actogonium divides dichotomically a little above the base, and the outer branch, that farthest from 

 the median line of the colony, soon divides again dichotomically into two. giving a slightly upward 

 curving phylactogonium with three short branches. These have only a single open row of strong 

 sarcothecse on the side turned towards the median plane of the colony; each branch has from three 

 to five sarcothecse. The branches of the phylactogonium are richly furnished with inner ribs, and are 

 also often irregularly segmented. The phylactogouia bear two or three gonothecae of the same type 

 as that usual in the genus, with a strongly developed upper lip domed out roofwise over the broad 

 opening, which is turned towards the phylactogonium. 



The colony from the "Ingolf" St. 46 exhibits the peculiarity of having the outer branch of the 

 seventh phylactogonium from below on the left side prolonged ; at the terminal point of the normal 

 branch arises a further lateral branch; the outer branch is further prolonged, and has, outside the 

 above-mentioned supernumerary branch, three hydrothecse, and thus from here presents the appearance 

 of a hydrocladium, which in addition to its basal hydrotheca further shows the incipient develop- 

 ment of a secondary phytoctogonium. The entire formation must be regarded as an abnormity. 



Cladocarpus bicuspis (G. O. Sars) Jaderholm. 



1874 Aglaophenia bicuspis, G O. Sars, Bidrag til Kundskaben ora Norges Hydroider, p. 98, pi. 2, figs. 7 — 10. 

 1909 Cladocarpus bicuspis, Jaderholm, Northern and Arctic Invertebrates, p. no. 



The colony is pinnate with polysiphonic, in the outer portions monosiphonic main stem. The 

 primary tube is divided into short internodia, each bearing an apophyse directed obliquely forward 

 and sideways, turned alternately to either side of the median line. The internodium is further provided 

 with three sarcothecse, a pair at the upper side of the apophyse, and an unpaired one in the median 

 Hue of the internodium, close below the apophyse; all are adcaulinally split. The internodia of the 

 hydrocladium have a very large hydrotheca and three sarcothecse. a supracalycine pair at the hydro- 

 theca aperture and an unpaired median proximal reaching up to the lower third of the hydrotheca : 

 all sarcothecse are adcladially split, and have quite smooth margins. The hydrothecse are laterally 

 much compressed, with outward curving opening margin, and with an abcauline pair of large teeth; 

 the margin otherwise smooth ; the sinus between the teeth is almost square. The teeth are concave, 

 the incurvation strongest at the median line. From the sinus between the teeth an inner rib runs 

 along the abcladial side of the hydrotheca to its middle, where it terminates in a strong S-shaped 

 intrathecal septum, dividing the hydrotheca into a larger upper portion and smaller basal part, the 

 latter half the size of the former. The internodium is furnished at the hydrotheca wall with four or 

 five short ribs, the proximal sarcotheca is bounded on the lower side by a an oblique septum: 



The gonotheese are situate on the stem or on short, dichotomically three- to four-branched 

 phylactogonia, proceeding from the basal internodium of the hydrocladium beside its proximal sarco- 

 theca. The phylactogonia are furnished with sarcotheca; irregularly arranged, and not infrequently 

 having indistinct segmentation. The gonotheca is somewhat flattened; from the broad side it is reversely 



The Ingolf-Expedition. V. -, 12 



