Catalogus

Three species have been found in recent years from the Plymouth district, two from the experimental raft moored near the Breakwater and from other fixed wood, and one from driftwood. The two commonly occurring from the raft are (1) T. norvegica and (2) a much smaller species carrying its young in a brood pouch, closely related to, if not identical with, T. navalis. The third species, occurring occasionally in driftwood, is T. megotara Forbes & Hanley. Purchon (1941), who worked at the last species from specimens in a tank at the Plymouth Laboratory, saw no sign of a brood pouch; and in those collected later from Wembury and examined by myself it was found that the eggs, shed directly into the sea, were very numerous.