Geographic Range

Other Physical Features

heterothermic 

bilateral symmetry 

radial symmetry

Development

Development is indirect, but non-metamorphic, with fertilized eggs of most species (with the exception of beroids) rapidly growing into ciliated cydippid larvae, which gradually attain adult sizes and morphologies. Lobates and cestids lose the characteristic paired feeding tentacles as they grow, while cydippid species retain them. Beroids lack tentacles at any developmental stage. (Brusca and Brusca, 2003; Wrobel, 2012)

Reproduction

Reproductive tissues develop within the meridional gastrovascular canals and gametes are expelled from the mouth, fertilization usually occurs in the water. In two benthic genera, Coeloplana and Tjalfiella, gametes are taken in through the mouth and fertilization is internal. Ctenophores are able to self-fertilize, although cross-fertilization with other individuals is also common. (Brusca and Brusca, 2003)

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  Mating System
  
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  polygynandrous (promiscuous)
  

Most ctenophores are simultaneous hermaphrodites, although some dioecious species are known, such as members of genus Ocyropsis. Members of order Platyctenida are also known to reproduce asexually, with small fragments that break off as the animal moves, developing into fully-developed adults. Most ctenophores are capable of reproduction before they reach adulthood (paedogenesis). As adults, ctenophores release gametes daily for periods of weeks. Gamete production may slow or cease if food becomes scarce. (Brusca and Brusca, 2003; Jaspers, et al., 2012; Mills, 2010)

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