Ultrastructural Studies of the Suckers of Newly Hatched Eledone Moschata and Octopus Vulgaris (Mollusca; Cephalopoda)

Abstract

Ultrastructural analyses give further information about the functional morphology of the suckers of newly-hatched benthic Eledone moschata and planktonic paralarvae of Octopus vulgaris and correlate these differences with the divergent developmental types within the octopod cephalopods. In E. moschata, each arm shows about 30 suckers. The structural features of the outer surface, the muscular system and the equipment with a well developed nervous system in the largest and most differentiated suckers correspond to the situation in suckers of adult animals. In O. vulgaris, only three suckers are situated on each arm. The retardation in the development of the muscle tissue and the lack of a differentiated subacetabular ganglion represent primordial conditions. On the other hand, the equipment with a large number of primary ciliated receptor cells seems to be significant in the planktonic paralarva.