The tergum hardly differs at all from that of B. cepa, but is perhaps of rather greater breadth.
tergum with a longitudinal furrow; spur with the end rounded.
The upper part of the tergum is not beaked, and does not project freely much above the sack.
The tergum precisely resembles that in some specimens of var.
I may remark, that in all the species of Lepas, the upper part of the tergum seems particularly variable.
On each side the tergum overlaps the sternum, and hangs down as a side-flap, or pleuron.
tergum without a longitudinal furrow; spur truncated, fully one third of width of valve.
The tergum also varies; in some individuals it is truncated and like that figured of var.
Lithotrya cauta, magnified between seven and eight times; (a), scutum; (b), tergum.
Page 51: scutum, S, being left articulated to the tergum, T.