Sub-Fam. 2. Diphyopsinae.—Diphyes.
Sub-Fam. 3. Abylinae.—Abyla.
These sub-families differ from one another in the character and shape of the nectocalyces and in other characters. They have a world-wide distribution, Diphyes and Galeolaria extending north into the Arctic Seas. Diphyes is British.
Fam. 3. Polyphyidae.—The nectocalyces are numerous, and superposed in two rows. The cormidia remain attached.
The family contains the genera Polyphyes and Hippopodius, both probably cosmopolitan in warm waters.
Sub-Order II. Physophorae.
In this sub-order the primary nectocalyx gives rise to a definite pneumatophore. There are four families.
Fam. 1. Physonectidae.—In this, the largest family of the sub-order, there is a monothalamic pneumatophore supporting a stolon, which in some forms is of great length, but in others is reduced to a stump or pad, on which there are usually found several nectocalyces, hydrophyllia, gastrozooids, gonozooids, and tentilla.
The principal sub-families are:—
Agalminae.—With a long stolon, bearing at the upper end (i.e. the end next to the pneumatophore) two rows of nectocalyces. The other zooids are arranged in cormidia on the stolon, each covered by a hydrophyllium. Dactylozooids with tentilla. Agalma and Cupulita, Mediterranean Sea.