Observations on the embryonic and early post-embryonic development ofRossia macrosoma (Mollusca, Cephalopoda)

摘要: 1. Egg masses ofRossia macrosoma were collected by bottom trawling in the Western Mediterranean. The ultrastructure of peculiar outer case egg is described. 2. embryonic development was followed at a constant temperature (15° C); graphic presentation developmental rates throughout embryogenesis given. Problems concerning length and course are discussed. 3. Embryogenesis briefly described figured. A few remarks made on organogenesis arm-funnel complex, alimentary canal, shell sac vena cava. Emphasis placed dynamics embryogenesis. 4. mechanism yolk absorption during later includes collecting transfer (to hepatopancreas) nutritive material means “vessels” (former sinus). 5. For hatching, secretory action Hoyle organ breaking case, which possibly facilitated muscular mantle “spine”. 6. Hatched animals raised laboratory for several months, under varying conditions. observations growth behaviour discussed, earlier field data being considered.