26 PENNATULIDA. 



Of this species, I have had the opportunity to examine a very large number 1 ), partly from 

 Danish seas, partly from various Scandinavian regions and from Iceland (the Vestman Islands). I 

 have been able to examine both well-developed and large specimens, to a length of 53O mm2 ), and also 

 young stages down to a size of io mm , i. e. smaller than those hitherto mentioned in the literature. 



In larger specimens I find the number of polyps in the developed wings very varying, from 12 

 to 4; specimens with three polyps in the wings or fewer are young stages which will be more particularly 

 mentioned later on. Kolliker, it is true, in his diagnosis of the species, states the number of polyps 

 to be 6 9, but in the more particular description, specimens occur with 10, with n 12, and with 3; 

 O. F. Miiller gives the number as 8, Dalyell 8 10. The lateral zooids placed under each wing 

 occur, in a corresponding manner, in varying numbers; where they are most numerous they are 

 grouped in two transverse rows, in the young stages in a single row and in a number almost similar 

 to that of the polyps. The peduncle is always shorter than the pen, but otherwise of very varying 

 relative length. When Kolliker says: Feder ungefahr 2'/ 2 3 mal lauger als der Stiel, his state- 

 ment is by no means always correct. The peduncle, here as in many other Pennatulids, may 

 obviously be stretched very much in the living state of the colony, and in a few preserved specimens 

 it may also be found much longer; in a specimen 350" long from the Kattegat I thus find it to be 

 250""" long (measured from the real boundary towards the rhachis at the cessation of the stalk-zooids). 



Of the numerous young stages examined, most, and especially all the youngest ones, belong 

 to the museum in Stockholm. They form together a rather close series, elucidating, I Ithink, the 

 essential facts of development and growth in the Virgularia. There is still, however, a regrettable 

 break between my youngest stage and the single primary polyp, the oozoite, which we know 

 hitherto only from Dalyell (I.e. pp. 188189). In the month of June, Dalyell succeeded in hatching 

 some planulae which swam about very actively (I.e. PI. XLVIII, fig. n); later, in July, he succeeded 

 in developing other planulse into the hydra form, i. e. into a solitary, tentacled, lengthy polyp (figs. 

 12 14) without any interior calcareous axis. Apart from the fact that the tentacles developed several 

 lateral branches, these polyps did not change during the period of more than a month, in which it 

 was possible to keep them living. As to the size, unfortunately, no more particular information is 

 given 3). 



In conformity with what is known of (Rcnilla and) Pennatula phosphorea, it is to be supposed 

 that this primary polyp grows in length, gains an interior calcareous axis, and develops on either side 

 a row of solitary polyp-buds following each other, as to age, from above downwards, so that a small 

 colony of the simplest penniform type is formed. Such a stage might be called the Protocaulon- 

 stage't). My youngest stages are of a form approaching very near to this supposed one, the only- 

 difference being that they are all wanting in a terminal polyp as the upper termination of the Stem. 



') Amongst these also, the specimens from our Museum mentioned by Kolliker in his Monograph. 



2) Kolliker, in his diagnosis, says: bis zu 345 mm lang. Dalyell, (I.e. p. 182) however, had already stated a length 

 of 23 inches, or about 585"]'". 



3) Dalyell evidently although with a cautious reservation thinks these young polyps to be, not the beginning 

 of the stem which they really are, but a first wing-polyp. His words are: ^Indulging conjectures regarding the incidents of 

 futurity is perilous; however, the survivance of a nascent animal might shew it to be the first of an originating lobe, that 

 the flesh is carried up in a solid mass beyond the bone, and that in this manner both ends of Virgularia are fleshy . 



4) After a genus established by Kolliker in Chall. Rep., but being really only a Virgularia ; see p. 30. 



