PENNATUUDA. 75 



I think most of them only young stages are known, and we know from U. encrinus that the 

 appearance of the species changes much during growth; no single investigator has been able to com- 

 pare to any considerable extent the many species established on more or less scarce material etc. 

 So much seems to be certain, however, that there is a number of species with well-developed spicula- 

 tion, and others where the spiculation is quite reduced, only the peduncle containing quite micro- 

 scopic spicules; others again are stated to be quite devoid of spicules, but, as will be shown with 

 regard to the two species more particularly mentioned below, not all the statements in this respect 

 are correct 



The following species have been described as devoid of spicules: U. encrinus (L.), magniflorti 

 K611., lindahlii K611., gracilis Marsh., geniculata Stud., and (I suppose) bairdii Verr. Apart from U. geni- 

 culata, with regard to which I can say nothing, I believe all these species to be closely allied; but as 

 long as the knowledge of the characteristics of the species, and their variability and changes during 

 growth is so uncertain, I think that some stress is to be laid on the geographical occurrence; thus, I 

 believe we may take it for granted that those of the mentioned species which have been found in the 

 Pacific, viz. U. magniflora and geniculata (and Studer's U. encrinus*} are specifically different from the 

 others which belong to the Atlantic and the Arctic Oceans; and further, as the whole group of Pemia- 

 tulids in its distribution within the northern parts of the ocean has proved to be remarkably depen- 

 dent on the bottom-temperature, there is every reason to suppose that the form which has been found 

 well- and even enormously developed within the cold areas, is specifically different from those found 

 in the < warm area of the Atlantic and the adjoining seas. On the other hand, I am inclined to regard 

 these latter U. lindahlii, gracilis, and bairdii as one and the same species. 



Umbellula lindahlii K611. 



Tab. Ill, Figs. 3746. 



Umbellula miniacea Lindahl. Kgl. Sv. Vet.-Akad. Handl. Bd. 13, Nr. 3, 1874, p. 12, PL I, II, Figs. 12 19. 

 pallida ibid. p. 13, PL III. 



Lindahlii Kolliker. Festschr. Phys.-Med. Gesellsch. in Wiirzburg 1875, p. 10. 

 gracilis Marshall. Rep. Triton >-Penn. 1883, p. 143, PL XXV. 



Bairdii Verrill. Am. Jour. Sc. (3) Vol. 28, 1884, p. 219 (Note) and U. S. Fish. Comm. Rep. 1883, 

 (1885), p. 509, PL I, Figs. 1-2. 



Two specimens of the genus Umbellula, taken by the clngolf; respectively east and west of 

 Greenland in the warm area, I consider to belong to the same species as the two specimens of 

 Lindahl from West Greenland. 



One of the specimens, from the deep part of the Davis Straits, is, I think, the smallest and least 

 developed stage hitherto known of the genus Umbellula. It has a total length of 48 mm , and appar- 

 ently consists only of the primary polyp (PL III, fig. 37); a closer inspection shows, however, that it 

 is provided with a somewhat great number of zooids (z) and a small bud of another polyp (p). The 

 developed polyp is supported by a fine narrow stalk, of which the lowermost 2 mm form an egg-shaped 

 swelling, of a diameter hardly i' mn ; this swelling is really the whole peduncle, as zooids appear 



10* 



