"a regular morphodite, in fact!"

Morphodite is a comic pronunciation of the the word hermaphrodite. It is used twice, for example, in Chapter 8 of Harper Lee's book To Kill a Mockingbird.

Morphodite, morphydite or moffie (in South Africa) are also sometimes used as a slang words for a homosexual.

Hermaphrodite (used as a noun and an adjective) is the name given to an organism (plant or animal) which has both male and female reproductive organs.

The situation with oysters is complex: they are dichogamous, protrandrous hermaphrodites; this means they have the ability to be both male and female, although not at the same time; they start life as male and become female later on.

 

Board illustrating the development of an oyster
Creative Commons Attribution Share AlikeBoard illustrating the development of an oyster - Credit: Ben+Sam, Flickr