Altogether the scuta and terga are attached, as far as muscles are concerned, to the shell and sack, by three longitudinal pairs. |
Operculum, or opercular valves.These consist of a pair of scuta and a pair of terga. |
Cavities in the scuta of the Female for the reception of the Males. |
Unfortunately the differences are not very great between the scuta of the different species. |
This articulation of the scuta and terga is prefigured amongst the Lepadid, in Pollicipes mitella, and in Lithotrya. |
The scuta are coloured either dull-purple or reddish, or striped longitudinally white and blue. |