PENNATULIDA. 



by a slight constriction. Unless the examination is thorough, however, the peduncle seems to begin 

 where the rudimentary wings cease. The stalk-zooids are never developed to polyps, but keep the 

 zooid-form '). 



3) New polyps are never seen in the act of formation at the ventral edge of the wings (as in 

 Pennatula and many other genera); this holds good not only of the whole region (a), but also far 

 down in (b); only in the smallest rudimentary wings are polyps seen to arise as elsewhere in the 

 Pennatulids; that is to say in such a way, that the most dorsal polyp in each rudiment is the oldest, 

 the most ventral one the youngest. One gets the notion indeed, that all the polyps belonging to a 

 wing are begun contemporaneously 2 ); certainly every wing, as soon as it has the character of a wing, 

 whether its polyps are fully formed or not, is provided with the number of polyps that it has 

 altogether. Nevertheless the polyp forming the dorsal edge of the wing continues always to be 

 the largest, the one terminating the ventral edge the smallest, even if the difference is often very slight. 



4) The calcareous axis has always a broken end above; it generally projects even with a 

 more or less long naked end from the sarcosoma. This is a well-known and often mentioned fact; 

 but it has been interpreted as due to injury, whilst I think it is caused by the mode of growth of 

 the colony (for further particulars see under V. mirabilis}. 



5) All the species of the genus are provided with the regular radiate canals in the rhachis, 

 pointed out by Kolliker. 



In all these features, and in several more, Halisceptrum agrees with Virgularia; it is quite 

 certain therefore, that the genus //. is to be referred to the same family as Virgularia; and it may 

 be doubted whether it ought to be maintained as a separate genus distinct from the latter. 



Virgularia mirabilis (O. F. Miiller). 



Pennatula mirabilis O. F. Miiller. Zool. Dan. Prodrom. 1776. 3074. 



Zool. Danica. The Danish edition 1781 (Straa-S0fjaeren), p. 43; the 



Latin edition. 1788, p. n, Tab. XI. 

 Virgularia mirabilis Lamarck. Anini. s. vertebres. 1816. T. II, p. 430. 



Kolliker. Monogr. 1872., p. 190. 

 Ljungmanni Koll. Monogr. p. 196. 

 vndtiflora Kner. Verhdl. k.-k. zool.-bot. Ges. Wien. 1858, p. 295. 



*) Kolliker has first seen these facts in Halisceptrum and in Virgularia; but in the description of what he calls 

 lateraler Zooidstreifen , he does not distinguish between the zooids that become partly the wing-polyps, partly the lateral 

 zooids placed under the wings, and those that continue to be zooids and to be arranged in a long single series; these latter 

 are the stalk-zooids. 



2 ) In this way the fact has been interpreted by Marshall; but everybody niay, by careful examination of the most 

 rudimentary wings, see that this interpretation is not correct. M., however, was scarcely in possession of any specimen with 

 this part of the rhachis fully preserved. Otherwise he seems to be the only author, who has especially observed the unvarying 

 nature of the number of polyps in the wings. See: Report on the Oban Pennatulida, 1882, p. 63. This little treatise, 

 which amongst many well-known things, contains several new interesting facts, is not found in our libraries, so that, when 

 in 1898 I communicated my conception of the mode of growth and development in Virg. mirabilis to the Natural History 

 Society here, I did not know that anyone had before observed the want of increase in the wings of Virgularia. The inter- 

 pretation of M. of the mode of growth, however, is essentially different from mine (see later). 



The Ingolf-Expedition. V. I. A 



OF THE ^ 



UNIVERSITY 



OF 



