. The Danish Ingolf-expedition. Marine animals; Marine animals; Hydrography; Hydrography; Scientific expeditions. HYDROIDA 41 extended polyp; they are without rings; at most tliere is some faint and irregular wrinkling here and there. The pol\p is fusiform with the tentacles irregularly distributed all over the surface; the pohp may be retracted into the broader distal portion of the hydrocaulus. The structure of the gonophores seems to be strongly reduced. They are developed at the uj^ier part of blastostyles without tentacles, at most i mm. high. Material: The P'aroe Islands: 13 miles West t
. The Danish Ingolf-expedition. Marine animals; Marine animals; Hydrography; Hydrography; Scientific expeditions. HYDROIDA 41 extended polyp; they are without rings; at most tliere is some faint and irregular wrinkling here and there. The pol\p is fusiform with the tentacles irregularly distributed all over the surface; the pohp may be retracted into the broader distal portion of the hydrocaulus. The structure of the gonophores seems to be strongly reduced. They are developed at the uj^ier part of blastostyles without tentacles, at most i mm. high. Material: The P'aroe Islands: 13 miles West to South of JNIunken, depth 150 fath. (on Citrdinin sp.). â â 9 â East vSouth East of Bispen, â 70 â ( - â - ).. 200 m. 6 00 175. .â ,. ......1000 »r7. Text-fig. L. Localities of Mcrona coriiucopiac ⢠and Monobrachium parasihit, 2000 m. in the Northern .\tlantic. Mcrona cornncopinr was first described as a Tiibiclava by Norman (1864). But as the latter genus is characterized by the gonophores being borne on the polyps, he thought he had better set up a new genus Mcrona (1865) for the species in hand, bearing its gonophores on polyps strongly reduced or on blastostyles. This criterion, however, is of subordinate importance and would by no means justify the separation of two genera. However, from the drawings occurring in literature, a much essential point of difference urges itself. The perisarc of the species of Tiibiclava is not so wide that the polyp can be retracted into it, while this is the case with Mcrona. The division, therefore, seems well founded. I^ut at any rate a renewed examination of tlic two genera is needed. Mcrona cornncopiac .seems only to occur attached to shells of living , and has been found on species of the genera Cardiitiii, Astartc. and Dcntaliiun. The species does not seem to be very frequent; it has been recorded from the sea to the north of the Slietlands at the depth of 80--100 , and from the coast of Northu
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Keywords: ., bookcentury1800, bookdecade1890, booksu, booksubjectmarineanimals
