Enigmatical viviparous chiton <i>Calloplax vivipara</i> (Plate, 1899) (Mollusca: Polyplacophora) and a survey of the types of reproduction in chitons
The chiton Calloplax vivipara was previously considered as ovoviviparous (Plate, 1899). However, six females of C. vivipara found on Chilean coast brooded both ova and juveniles in their pallial grooves. Therefore, the data of Plate (1898, 1899) about ovoviviparity in C. vivipara are to be considered as wrong. The present study discusses four patterns of reproduction in chitons: free spawning of separate eggs into open water; spawning of eggs as a mucous mass or string on a bottom; spawning of eggs into pallial grooves of a female, where eggs and larvae are brooded; spawning of eggs in an egg hull (egg capsule) on macroalgal thalli. The tables with lists of brooding species of chitons are included in the paper. Four brooding species have been recorded for the first time, thus increasing the number of brooding species of chitons to 41.