. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. 50 HYDROIDA Dicoryne co7iferta (Alder) as to confusion, and the two species have probably more than once been mis- taken for one another. Both the species have styloid gonophores; but in Heterocordyle they are ses- sile, while in Dicorync^ when ripening, they assume cilia all over, develop two tentacles, and break away. This is, unquestionably, a phenomenon of mere biological adaptation and cannot be recognized as sufficient for distinction of genera as long as it is not accompanied by a t
. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. 50 HYDROIDA Dicoryne co7iferta (Alder) as to confusion, and the two species have probably more than once been mis- taken for one another. Both the species have styloid gonophores; but in Heterocordyle they are ses- sile, while in Dicorync^ when ripening, they assume cilia all over, develop two tentacles, and break away. This is, unquestionably, a phenomenon of mere biological adaptation and cannot be recognized as sufficient for distinction of genera as long as it is not accompanied by a thorough change of the organization of the sterile parts of the colon)-. It is evident that Dicorync and IJelcrocordylc must be drawn together into one genus, and moreover that this genus must be united with Text-fig. O. The habitat of Ikmgainvillia conferta in the Northern Atlantic. (In the hatched regions the litterature denotes the occurence of the species without strict locahties). Bougainvillia conferta (Alder). 1856 Eiidrmiriiiiii coii/i-rfnii/^ Alder, A Notice of Some New Genera and Species of British Hydroid Zoophytes, p. 354, pi. 12, fig. 5-8. The colonies attain a height of up to 15 mm., and exhibit a rigid appearance. They have a distinct main stem witli short side-brauclies. The perisarc is vigorously developed and dark brown- coloured. The small fusiform polyp attains a length of al)out mm.; it wears about 16 tentacles in a single whorl below tiie oral conically pointed portion. The gonophores are stvloid and Ijreak away. When ripening, they assume a peculiar oviform shape, develop two filiform tentacles, and \n\i on a complete suit of cilia all over. The gonophores are seated, gathered in a belt, somewhat t^elow the apex of blastostyles, which arise from the hydro- caulus or, in smaller numbers, from the hydrorhiza. The blastostyles show no indication of Please note that these images are extracted from scanned page images that may h
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