a variously-formed limb, and serving as protection to the mouth of the cell in front.  The cavity of the tube by which the process arises, becomes, in the expanded portion, continuous with variously disposed grooves or channels, which terminate at the edges of the operculum.  This organ affords excellent specific characters (not in this genus alone).  Besides the sessile avicularia above noticed, many species of this genus also possess avicularia of another kind, and which are placed on the front of the cell below the opening and towards the inner side, or in other words, towards the middle line of the branch.  In this genus, in all those species in which the second avicularium occurs, each individual cell is provided with one.  This additional avicularium appears to be composed of a flexible material, and it is very easily broken off, so that in many instances, perhaps throughout an entire specimen the organ itself may be wanting, although its position is clearly evidenced by the existence of a rounded opening in the usual situation of the organ.  It is necessary to distinguish this form of flexible (if such it be) avicularium from the truly articulated and movable avicularia, in the form of birds’ heads, and which form does not occur in the genus Scrupocellaria.

a.  OPERCULATAE.  Cells furnished with a pedunculate operculum.

1.  S. cervicornis, n. sp.

Veins or channels in the oral operculum, branching so as to resemble the antlers of a stag.  The marginal spine next above the pedunculated operculum, bifurcate.

Habitat:  Off Cumberland Islands, 25 fathoms, fine grey mud.

A small, delicate, parasitic species, very transparent.  The very peculiar markings on the operculum at once distinguish it.  The upper margin of the mouth is furnished with five elongated spines, the innermost of which is forked at the extremity.

2.  S. diadema, n. sp.

Cells elongate, external side nearly straight, vibraculum sublateral, very prominent.  Limit of operculum entire, or obscurely bi-trilobed.  A flexible avicularium in front.  Ovicell usually with a single row of four or five openings immediately above its mouth.

Habitat:  Moreton Bay.

b.  INOPERCULATAE.  Cells without a pedunculate operculum.

3.  S. cyclostoma, n. sp.

Opening of cell nearly or quite circular, margin much thickened, with three or four short indistinct spines above.  Vibraculum sublateral.  A flexible avicularium in front.  Ovicells —–­ ?

Habitat:  Bass Strait, 45 fathoms.

4.  S. ferox, n. sp.

Opening of cell broad oval, pointed below; three short indistinct spines above; vibraculum large, sinus deep.  An enormous anterior avicularium, as wide as the cell.  Ovicell lofty, with numerous punctures over the surface.

Habitat:  Louisiade Archipelago.  Bass Strait.

Distinguished from the former species by the enormous anterior avicularium, and the form of the opening.  Another peculiarity of this species is the curious serrated appearance of the radical tubes.