1899] THE FAUNA OF. THE. SOUND 267 
been found off Greenland; only 2 or 3 are southern, and 2 inter- 
mediate. The northern character is even more manifest when one 
includes all species recorded in hterature as found in the Sound, many 
of them, however, at its northern boundary. Fully half of the 48 are 
northern, and only one purely southern. The Chaetopod faunas of the 
Skagerack and Kattegat, on the other hand, contain more southern 
elements, and especially a large number of species with west European 
distribution—neither Arctic nor southern—a group that is but sparingly 
represented in the Sound. 
The Bryozoa have not yet been thoroughly worked out; but of the 
9 species found, as well as those previously recorded, Membranipora 
membranacea is the only purely southern form; the rest are either 
northern or wide-ranging, but for the most part found in Arctic seas. 
The Echinoderma, of which there are 19 species, have a distinctly 
northern character. The 3 holothurians are northern. Five starfish 
are northern; the sixth, Asterias hispida, now first found in Swedish 
waters, is a Shetland form. Of the sea-urchins, 1 is northern and 
wide-ranging. The brittle-stars comprise 3 northern forms, 2 wide- 
ranging, but tending more to the south, and 2 (alone among the 
Echinoderms) purely southern. There are in the Kattegat 18 more 
species of Echinoderma than in the Sound, and it is most suggestive 
that of these 8 are southern, 7 intermediate, 1 wide-ranging, and only 
2 northern. Obviously the Echinoderm-fauna of the Kattegat is far 
more southern in its composition than is that of the Sound. So, too, 
among the 29 species of Echinoderma, known from Helgoland, only 9 
are northern, the rest being wide-ranging or southern forms. 
Only 16 species of Hydroidea have as yet been determined, but 
these add Acaulis primariuvs and Cuspidella grandis to the list of the 
Swedish fauna, while Zovenella producta and Opercularella lacerata have 
not before been found in Oresund. This part of the fauna has a 
northern character, more pronounced than that of SBohusliin, for 
example, from which, though it les farther north, many of the 
northern species are absent. 
The list contains notes on other zoological groups, but nothing of 
sufficient importance to be mentioned in this short abstract. The 
foregoing account is based on Dr. Lonnberg’s first and larger paper ; 
the second paper adds only three or four species, among which may be 
mentioned the new Hydroid, Clava glomerata (see Zoologischer Anzeiger, 
No. 578). 
As already observed, the chief factor in the distribution of species 
within the Sound itself is the nature of the bottom. Dr. Lénnberg 
distinguishes the following regions and sub-regions: Shore-regions ; 
Zostera-region; Alga-region, with Laminarian, Furcellarian, and Coral- 
line sub-regions; deep-water, with bottom either of dead zostera, or 
mixed, or sand, or clay. Of course each of these divisions merges into 
those adjoining, but on the whole they may be characterised thus :— 
