Carinoportulae

A type of central process unique to the genus Orthoseira. The internal openings are simple, while the external openings are composed of well-defined collars.

O Roeseana Carinoportulae
Image Credit: Marina Potapova
Image of the valve face of Orthoseira roeseana, showing three carinoportulae. The number of carinoportulae present is variable across populations.
Carinoportulae
Image Credit: Marina Potapova
SEM image of the internal expression of carinoportulae in O. roeseana.