24 THE NAUTILUS. 



many years the principal extended sources of information upon this 

 subject. The paper of Mr. Odlmer is based upon the large collec- 

 tion of Northern and Arctic forms which the Swedish State Museum 

 has accumulated from various expeditions and other sources since its 

 foundation, and which have been studied in part only by scientists. 

 The geographical area represented is a wide one, nearly completely 

 circumpolar in its extent. It includes principally the Arctic Ocean 

 off Siberia, the Kara and White Seas, the Arctic and Atlantic Oceans 

 off the coast of Norway, the waters surrounding the whole Scandi- 

 navian peninsula, and to a less extent the coasts of Spitzbergen, 

 Iceland and Greenland, the North Atlantic, Davis Strait, Baffin Bay 

 and Bering Sea. 



The first section of the paper gives a useful systematic synopsis of 

 the Opisthobranchs and Pteropods studied, based largely upon the 

 well-known works of Fischer, Bergh and Pelseneer. Following 

 this is a detailed summary of the geographical and bathymetrical 

 distribution. 



The third section of the work is devoted to a description of the 

 new forms found in the collection. These are Diaphana hyaUna 

 Turton var. spirata, Diaphrma fffaciah's, GonifPolis lobata, Archi- 

 doris -nobilis Loven MS., Is&a villosa, Doridunculus pentnbranchus, 

 Idalia pulchello A. & H. var. fusca, and Cumanotus laticeps, the last 

 named being the type of a new genus of Aeolidiadae. 



Of especial interest and value to students of this group of Mollusca 

 are the three excellent plates, the second and third being especially 

 welcome. These two present artistic reproductions in the natural 

 colors of sixty-one figures of forty-one different species, prepared 

 under the direction of Professor Loven by the artists W. and F. v. 

 Wright, but never yet published. These form a valuable supple- 

 ment to Loven's Index, the original numbers assigned by him being 

 given in parentheses upon the plates. Those who have studied these 

 beautiful animals in life and compared them with even the very best 

 museum specimens, in which original color and body form have 

 alike disappeared, will fully appreciate this preservation in a perma- 

 nent manner of these important records. 



The usefulness of the paper is further enhanced by a chronolog- 

 ical bibliography and a very complete index. The convenience of 

 the former might have been increased somewhat by the addition of 

 abbreviated titles of all the papers cited, which are omitted in most 

 cases, the date, author, journal and place alone being given. 



