The following account nf the pallial complex of the Tectibranch Dolabella is, as regards the minuter details, founded on a single specimen (Dolabella rumphii) kindly sent me by Professor M'Intosh of St Andrews. By an examination of the collection in the South Kensington Natural History Museum I was enabled to verify for the genus points which might have been peculiar to this species, and in one point to note an important variation.

A few words as to the necessity of an accurate description of the pallial complex or system of organs in the mantle cavity of the Opisthobranchiata, and the inferences that may be drawn, may not be out of place.