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 o;enus Lainpra 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 Lanipra had already been applied to a subgenus of the 

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

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

 nwrplia are not sufficient to justif>' a separation of genera. 



A closer examination of the numerous northern species of Lainpra 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 discriptiou given by Allman (1876) is founded on a series of young individuals 

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

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

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

 able, we here face one of the reasons of the great varying of the nuiubers 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 fiugerformed bulges of the polyp wall. The 

 gonophores only appear at a rather late stage of development. 



The skeletonlike figures and rather deficient diagno.sis of the species given by Allman long 

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

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

 accordingly describes two new, closely related species, L.ampra atlantica and L^ampra purpurea. 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 ni 

 the single specimen of Lampra pjcrpnrea 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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