36 PENNATULIDA. 



whatever that their three species will have to be united into one. Further from an examination of 

 the type-specimens of the genus Svava of Danielssen and Koren (North-Atlantic Exp. Penn. p. 45) 

 the species Sv.glacialis with the var. alba I have convinced myself that this genus agrees in every 

 respect with the zCladiscus-species* 1 ); here also &ventral-zooids of the same kind and the same 

 arrangement as in these species may easily be detected; they may always be seen - - even under a 

 magnifying glass when the specimen is cleared in oil of cloves, or, what is often better, in bergamot. 

 But if the same method is used with regard to any tolerably well-preserved specimen of Virgularia 

 mirabilis, the very same ventral zooids will also be found there, arranged in the same way, only in 

 far greater numbers and in several layers. The fact is that these so-called ^ventral zooids>, which in 

 some specimens of Cladiscus- are seen so easily, in others only with difficulty unless in a clearing 

 medium, are not at all zooids, but on the contrary the ,radiate canals* described by Kolliker 

 in Halisceptrum and Virgularia. There can be no question therefore of maintaining genera like 

 Cladiscus and Svava; they are one and the same species, and this species must belong to the old 

 genus Virgularia; it is even very closely allied to the species mirabilis; indeed, young specimens of 

 this latter species with the same number of polyps in the wings can with difficulty be distinguished 

 from Virg. cladiscus mihi ; on clearing, the young V. mirabilis also show radiate canals in smaller numbers 

 and in a single layer; the polyps, however - - whose degree of coalesence in V. mirabilis is somewhat 

 varying, -- are never so slightly coalesced as in V. cladiscus, and distinct calyx-teeth, at all events, 

 are not found. That the species V. cladiscus may be provided with more than four polyps in the 

 wings is seen in a couple of specimens from the Dutch Barents-Expedition (1881) now before me, 

 which have five polyps in the wings (whilst others specimens from the same expedition have four 

 or three polyps in the wings), as also in a specimen from Finmark, Grolsund, and one from the Skager 

 Rak (both belonging to the Stockholm Museum): and Grieg (I.e. p. n, under Svava glacialts) men- 

 tions a specimen from Trondhjem Fjord with up to six polyps. A young stage, with two polyps in 

 the wings, two lateral zooids, 52""" long, from the Skager Rak, is found in the Stockholm Museum. 

 This species may also vary in the way in which the polyps of the separate wings are connected, and 

 partly also in the degree of their coalescence (comp. Grieg 1. c. p. 19). 



That I have also enumerated Virg. tuberculata Marshall among the synonyms will require no 

 long explanation. From the description in Rep. Penn. Triton pp. 129 133 and from the figures, 

 every one will easily recognize its identity; and moreover, this specific name has been withdrawn in 

 the later work by Marshall and Fowler (Rep. Penn. Porcupine*, p. 464), on account of its identity 

 with Cladiscus gracilis Kor. & Dan., and it is added that these authors find the generic characters as 

 given by the Norwegian authors too slight to justify a separation of the form from Virgtilaria* 2 ) one 

 must certainly allow that they are right here, although they pay no regard to the false ventral zooids 

 whose nature was unknown to them. Strange to say, the same authors have retained Svava glacialis, 



') The description by Danielssen and Koren of the genus Svava, agrees so well with the one given earlier of the 

 genus Cladiscus, that it is astonishing they have not themselves seen the identity. And when it is stated for Svava that the 

 generative organs are only developed in the lower, imperfect polyps, whilst the upper, perfect ones are sterile, it is also strange 

 that their attention was not immediately drawn to the genus Virgularia, with regard to which Kolliker had long ago pointed 

 out the same fact. 



2 ) Marshall figures no lateral zooids in his V. tuberculata; from his remarks on p. 132 it is seen, however, that he 

 has noticed them, but does not venture to state them as certain. 



