. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. PENNATULIDA. I have followed KoHiker in regard to the terminology; some of his terms have been used from much older times, and are based on the external [resemblance to a feather, especially conspicuous in forms like Pennatula, Pteroeides etc. The stem of the colony is accordingly divided into the shaft, rhachis, carrying all the individuals, and the peduncle, which is naked and under natural conditions sunk into the bottom of the sea; polyp is the name used only for the individuals posses
. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. PENNATULIDA. I have followed KoHiker in regard to the terminology; some of his terms have been used from much older times, and are based on the external [resemblance to a feather, especially conspicuous in forms like Pennatula, Pteroeides etc. The stem of the colony is accordingly divided into the shaft, rhachis, carrying all the individuals, and the peduncle, which is naked and under natural conditions sunk into the bottom of the sea; polyp is the name used only for the individuals posses- sing the entire equipment of an octocoral, tentacles etc., zooid for the dwarf individuals wanting sexual organs and tentacles (onI\- in Umbellula do they carry one tentacle). The individual is said to be provided with a cal\-x, when the basal part of its body >) is stiff so as not to be retractile, but the upper part of the pohp with mouth and tentacles can be retracted and hidden in it. The upper edge of the calyx may be more or less marked, in the former case it is provided with lobes, up to eight in number; the axial (dorsal) side of the individuals is turned towards the stem, the abaxial (ventral) away from the .stem. Wings, alse or pinnae, is the name of the oblique series of polyps placed transversely on the stem, where the polyps are mutually coalesced. I have differed onh' in one j^oint from Kolliker; what he de- scribes as the ventral side of the colony, I call the dorsal, and vice-versa (excej^t in Rcnillw see below); this I shall try to explain more closely. In the great majority of Pennatulids the colony, as is well known, is constructed bilaterally. The plane that divides the stem longitudinally into two corresponding parts, has quite naturally always been interpreted as a dorso-ventral one (V—D in the annexed figure); but whether the side of the stem in the figure denoted by D, is to be called the dorsal (po- sterior), or the \-entral (anterior), has alway
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Keywords: ., bookcentury1800, bookdecade1890, booksu, booksubjectarcticregions
