Literature. 



Most of the works mentioned in the preceding pages are to 

 be found m Ludwig's excellent Bibliography (1900), to which I 

 beg to refer. Here I only mention such publications as are not 

 included in his list. 

 BiDENKAP, 0.: TromsOsundets Echinodermata. Tromso Museums 



Aarshefter, Bd. 20, 1897. Tromso 1899. 

 Danielssen, D. C. : Beretning om en zoologisk Reise i Sommeren 



1858. Det Kongel. Norske Vidensk. Selskabs Skrifter 



1846—1859. Trondhjem 1859. 



— Beretning om en zoologisk Reise foretagen i Somme- 

 ren 1857. Nyt Magazin for Naturvidenskaberne, Bd. 11. 

 Christiania 1861. 



HÉROUARD, E. : Holothuries provenant des campagnes de la Prin- 

 cesse Alice (1892 — 1897). Resultats des campagnes scientif. 

 accomplies sur son yacht par Albert I, prince souverain 

 de Monaco. Fase. XXI. Monaco 1902. 



LuDwia, H. : Arktische und subarktische Holothurien. Romer 

 & ScHAUDiNN, Fauna Arctica, Bd. I. Jena 1900. 



NoRDGAARD, 0. 1 Somo Hydrographlcal Results from an Expedition 

 to the North of Norway during the Winter of 1899. Ber- 

 gens Museums Aarbog, 1899. Bergen 1899. 



Ortmann, a. E. : Grundziige der marinen Tiergeographie. Jena 

 1896. 



Ostergren, Hj. : Zur Anatomie der Dendrochiroten, nebst Be- 

 schreibungen neuer Arten. Zoologischer Anzeiger, 1898. 

 [1898 a]. 



— Das System der Synaptiden (Vorlauf. Mitteil.) Ofver- 

 sigt af Kongl. Vetenskaps-Akademiens Forhandlingar 1898. 

 Stockholm. [1898 b]. 



