|
|||||
|
|
Larval development and metamorphosis in the marine pulmonate Amphibola crenata (Mollusca: Pulmonata) |
|
| Authors: | C Little Penny Stirling Margaret Pilkington and J Pilkington |
| Institution: | Portobello Marine Laboratory and Department of Zoology, University of Otago, Dunedin, New Zealand |
| Abstract: | The development of the free-swimming veliger of Amphibola is followed from hatching to settlement, and the larval structures compared with those of post-metamorphic juveniles and adult snails. Observations of living specimens and light-microscope sections were combined with scanning electron microscopy to build up a composite picture of veliger structure. Four stages in the development of veligers are recognized, each being characterized by the appearance of organ systems such as the mantle cavity, larval heart, adult heart and kidney, and larval pallial gland. At or after metamorphosis, the larval systems (heart, kidney and pallial gland) disappear, and the developing adult organs move to the positions characteristic of adult snails. Organogenesis in Amphibola veligers is compared with that of prosobranch and opisthobranch larvae, and with that of pulmonate larvae with direct development. The closest similarity is seen to be with opisthobranch veligers. |
| Keywords: | |