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Males of Xenopus laevis, maintained in constant experimental conditions, when placed with females injected with gonadotrophin and ovulating ("hot" females) in small aquaria, clasp them (assault) and remain clasping for hours, until after fertilization. Placed with females not so treated ("cold" females) or with males, they also assault, but only remain clasping for a few minutes, then unclasping and after an interval repeating the process. Thus a sequence of Clasping Spells is obtained. This paper deals with the position of the clasp on the body of the passive partner (the animal clasped). The assault on any passive partner may be on a great variety of different parts of the body, the part concerned being called the assault position. During a spell, rapid unclasping may occur, followed by immediate reclasping on another part of the body, called the adjusted position. Several such adjustments may occur in one spell. The commonest sequence of positions on a hot female is: Thigh (assault) - Waist (adjusted). On other passive partners a great variety of sequences may occur. Assault positions on hot females are on the thigh or waist in 85% of observed assaults. On cold females and males, the percentage is significantly lower, and is correlated with a variable in the central nervous system of the active partner called Clasping Tendency, associated with clasping behaviour. This correlation is taken as evidence of a relation between two functionally distinct types of control mechanism, previously distinguished as Determination and Ajustment. The percentage is not significantly different between assaults on cold females and those on males. To account for the observed facts, a hypothesis of three orientation mechanisms is presented, with a discussion on the role of guiding stimuli. It is shown that the behaviour so generated would be adaptive, and bears an adaptive relation to the system of mating behaviour previously inferred for Xenopus laevis and other Anuran species.