. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. HYDROIDA 55 From the reptant stolons proceed polyp stems up to 12 mm. long, generally unbranehed; more rarely 2—4 polyp stems proceed from a common trunk, 1—2 mm. high. The polyps attain a length of mm., and are fusiform, with 6—12 tentacles placed in a whorl. Below the tentacles the polyp is surrounded by a psendohydrotheea, which it is very difficult to observe on the polyp when wholly extended. In general it is jellied and vigorously developed. The polyp stems are, particularly in their proximal part, irregularly wrin
. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. HYDROIDA 55 From the reptant stolons proceed polyp stems up to 12 mm. long, generally unbranehed; more rarely 2—4 polyp stems proceed from a common trunk, 1—2 mm. high. The polyps attain a length of mm., and are fusiform, with 6—12 tentacles placed in a whorl. Below the tentacles the polyp is surrounded by a psendohydrotheea, which it is very difficult to observe on the polyp when wholly extended. In general it is jellied and vigorously developed. The polyp stems are, particularly in their proximal part, irregularly wrinkled. The very large gonophores show no medusoid structure; they are attached to the reptant sto- lons by a short stem. Material: Greenland (Lille Hellefiskebauke) (the original specimen of Garveia groenlandica Levinsen). An examination of the original specimen of Garveia groenlandica shows no difference at all from Norwegian specimens of Perigonimus rosats. The species are no doubt identical. If we compare Kramp's drawing of Garveia groenlandica (1911, pi. XXV, fig. 6) with Jaderholm's figure of Pe- rigoi/ii/uts rosats (1909, Taf. Ill, Fig. 7), there may, at the first glance, seem to be some points of difference. Thus the stems of the specimen mentioned by Kramp are much shorter. But this character proves of little significance if we compare the specimen with a larger colony, where, as a matter of fact, the length of the polyp stems varies greatly. A greater stress might, on the other hand, be laid on the apparently great difference between the psetidohydrothecae as represented in the two figures. However, much depends on the contraction of the polyps and on the state of preservation, as is plainly to be seen by an inquiry into a larger material. I have several times had the opportunity of observ-. 20om. 600 m. tooom. 2000m. Text-fig. R. The occurence of Perigonimus roseus in the Northern Atlantic. (In the hatched region the occurence according to the litterature is comm
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectscientificexpedition
