Nr. 5] THE CEPHALOPODA DIBRANCHIATA 7 



(p. 2) it is called Eledone octopodia Pennant. At the Biological 

 Station of Bergen we sometimes kept E. cirrosa living in an aqua- 

 rium, but it could not live there for longer time than 1 month as 

 a maximum. Once (^7^ 1900) I saw a specimen of Eledone make 

 preparations for eating a dead Gadus v irens. Several times the 

 animal cleaned its food by directing a water-current from (he fun- 

 net to the little fish Nordgård, 1911, p. 43). I also saw in Eledone 

 the sudden changements of colour wich are characteristic of some 

 Cephalopoda. The biological meaning of this manifestation of life 

 has been explained f. i. by Leon Fredericq de Liége (1889, p. 214 

 — ^227) who writes: «Cest chez les Mollusques céphalopodes, Poulpe, 

 Seiche, Sépiole, Calmar, etc. que la fonction chromatique 

 atteint pour ainsi dire son maximum de développement. Les chan- 

 gements de coloration les plus étendus oopérent chez ces Animaux 

 par le jeu des chromatophores, avec la rapidité de Téclair. Ces 

 changements ont fréquemment, comme chez les Poissons, pour but 

 d'harmoniser le ton de TAnimal å celui du fond sur lequel il vit et 

 constituent done des cas de m i m é t i s m e». 



2. DECAPODA. 



Rassia macrosoma Delle Chiaje. 

 Rossia oiveni Lønnberg, 1891, p. 15. 



— macrosoma Massy, 1909, p. 19. 



In V. Storm's collections there are several specimens from Ro- 

 berg, and 1 specimen from the island of Leksa, outside the Trond- 

 hjem Fjord, found in July 1899. To this I may add the following 

 finds: February 1909. Gaulos (2 specimens); "^ 1911. Gaulos (1 

 specimen, length from end of body to ventral edge of mantle 

 52 mm.). Appelløf (1892, p. 7—9) has made it probable that 

 R. oweni Ball = R. macrosoma Delle ChIaje. Lønnberg (1881, 

 p. 15 — 16) also pointed at tht insufficiency of the separating cha- 

 racters. The paper of the original decription of R. macrosoma is 

 noted by Locard (1886, p. 12). Delle Chiaje named the species 

 Sepiola macrosoma. R. Owen (1800—1892) instituted in 1835 the 

 genus Rossia for a cuttle-fish which was brought home by the ex- 

 plorer of Arctic regions, Sir John Ross (1777—1856). The known 

 distribution of R. macrosoma is: The Azores and the Mediterra- 

 nean to the Trondhjem Fjord. The occurence of this species at 

 Spitsbergen ought to be verified. A. confounding with arctic spe- 

 cies as R. palpebrosa Owen or R. mølleri Steenstrup is not beyond 

 doubt. The genus Rossia seems to belong especially to the north- 

 ern part of the world, but of late years a species is described from 

 Australia, viz. Rossia (Austrossia) australis Berry (1918, p. 253, 

 pl. 69, figs. 3, 4, pl. 70). In the years 1895—1905 I sometimes dred- 

 ged R. macrosoma in the Herlofjord at Bergen and I also found 



