HYDROIDA 



35 



The species, which is widely distributed in the deeper parts of the cold area, has been found by 

 several expeditions, and has formed the base of the genus Lampra stated by Bonne vie (1898, 1899). 

 I have already in works earlier published pointed out that, for several reasons, this genus cannot be 

 maintained. In the first place, the name of Lampra had already been applied to a subgenus of the 

 beetle family Buprcstidac^ and should, therefore, disappear among the hydroids, according to the rules 

 of nomenclature internationally adopted. Secondly the characters distinguishing Lampra from Cory- 

 morplia are not sufficient to justif)' a separation of genera. 



A closer examination of the numerous northern species of Lampra described will show their un- 

 maintainability. A survey of the figures forming distinguishing characters is obtained by grouping the 

 criteria stated as follows: 



The original discription given by Allnian (1876) is founded on a series of young individuals 

 from Godthaab, in which it may be observed how the number of proximal tentacles increases by new 

 tentacles being established and growing out among the old ones. How far the number of tentacles 

 may increase in this way, cannot be settled. I!ut no definite rule of the increase being trace- 

 able, we here face one of the reasons of the great varying of the numbers of tentacles. In these young 

 individuals it is also interesting to observe that the distal tentacles are established quite irregularly 

 Tab. II Fig. 14), and that the blastostyles arise as simple fingerformed bulges of the polyp wall. The 

 gonopliores only appear at a rather late stage of development. 



The skeletonlike figures and rather deficient diagncsis of the si)ecies given by All man long 

 impeded its recognition, and, therefore, only a couple of specimens occurring in the museuui of Copen- 

 hagen have later on been correctly referred to his species Monocaulus groenlandica. Bonnevie (1899) 

 accordingly describes two new, closely related species, Lampra. atlantica and LMVipra purptirca. The 

 former species is distinguished from the latter mainly by its small number of tentacles, having only 

 ten proximal ones. However, even though this difference must be regarded as very large, as far as in 

 the single specimen of Lampra purpurea as many as thirty proximal tentacles have been observed, 

 we cannot acknowledge it as a sufficient specifical distinguishing character after the examination of a 

 larger material of the .species. The rather numerous specimens found in the Trondhjem fjord present 



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