ABSTRACT

" Review of spawning and development in the Sacoglossa (Mollusca,Opisthobranchia) "

Reproductive data for more than 80 species of Sacoglossa are summarized.
The correlation between capsule size and development type is confirmed.
Development pattern is not related to phylogeny, neither at family nor genus level. The number of species with non-planktotrophic development appears to be higher in the Caribbean than in any other zoogeographic regions. This is interpreted as an example of local (sympatric) speciation. Cladistic analysis may help to resolve this.
Penial morphology is another reproductive character which appears to have been important in speciation. Loss of penial armature could be a single gene mutation; this has apparently occurred repeatedly in sacoglossan phylogeny and may serve as a rapid means of reproductive isolation.
Extra-capsular yolk occurs only in the superfamily Plakobranchoidea. Its function and origin are still debated.
Information on spawning behaviour is very scarce as is information on aspects of fertilization. The existing information is summarized and its phylogenetic and evolutionary importance discussed.

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