Note 1 — DIVISION II. PLEUROCARPI.

This name has been wrongly given to some half-dozen different species; but I am informed by Dr. Braithwaite (in lit. 29, Mch. 1872), that he has recently consulted the original specimen of Dillenius on which Linnæus founded the species, and from his examination the synonymy of this group must be altered as above. The diagnoses of this and the next four species are from his pen; the name aduncum should be retained as being older than exannulatum.