title: The Behavior of Heterolepidoderma sp. (Gastrotricha).
abstract: The behavior of Heterolepidoderma sp. was studied with the same approach as those already used for many species of ciliates. The ethogram we drew comprehends both helicoidal swimming (n = 20, r = 52.5 +/-12.2 mum, pitch = 512 +/- 101 mum, v--> = 215 +/- 43 mum/sec), periodically interrupted by irregular patterns changing the direction of the swimming of random angles and creeping on the substrate. The latter behavioral state, very common for the species we studied, occurs along tracks formed by successive elements (circular, C, vs linear segments, S) joined to each other by two kinds of reactions, which change their trajectory. The surprising similarities and the unexpected differences between the behavior of this gastrotrich and those of the ciliates already studied from this point of view are discussed, on the basis of the dimensional ranges and ecological niches shared by these two, definitely unrelated groups of organisms.
authors.forename: R
authors.initials: R
authors.lastname: Banchetti
authors.forename: R
authors.initials: R
authors.lastname: Nicola