3.  IDMONEA, Lamouroux.

1.  I. radians, M. Edwards.  Ann. de Sc.  N. tome 9 page 25 plate 12 figure 4. 
Retepora radians, Lamarck. 
Habitat:  Bass Strait, 45 fathoms.

One minute specimen, but very perfect, has been examined; but it is undoubtedly the one described and figured by M. Edwards, and noticed by Lamarck as inhabiting the seas of New Holland.  M. Edwards’ doubt therefore as to this locality is now removed.

Fam. 2.  CRISIADAE.

4.  CRISIA, Lamouroux.

1.  C. denticulata, Fleming.  Habitat:  Bass Strait, 45 fathoms.

Parasitic upon a species of Salicornaria.  The only difference, if there be any, between this form and the British, consists in the rather greater projection or freedom of the extremities of the cells, which are curved towards the front.

2.  C. acropora, n. sp.

Cells 9 to 13 in each internode; lateral branches given off between the first and second, or between the second and third cells above a joint.  A small conical tooth, sometimes bifid, above and behind the mouth.

Habitat:  Bass Strait, 45 fathoms.

A small parasitic species, distinguished from C. denticulata, which it much resembles, by the less average number of cells in each internode, and the less number intervening between the origin of a branch and the joint below it, and by the small conical tooth or tubercle above and behind, or to the outer side of the mouth.

Suborder 2.  CHEILOSTOMATA.

Sec. 1.  Uniserialaria.  Cells disposed in a simple series.

Fam. 1.  CATENICELLIDAE.  Cells connected by flexible joints.

5.  CATENICELLA, M. Edwards (Lamarck An. s.  Vert. tome 2 page 181.)

Cells arising one from the upper and back part of another by a short corneous tube, and disposed in a linear series, all facing the same way, and forming dichotomously divided branches of a phytoid polyzoary; cells geminate at the bifurcation of the branches; each cell furnished with two lateral processes usually supporting an avicularium.  Ovicells either subglobose and terminal, or galeriform and placed below the mouth of a cell in front.

This interesting and important genus may be regarded as characteristic, not only of the present collection, but perhaps also of the Australian seas, as far as the Polyzoa are concerned.  Thirteen species are here described, and as it has been found extremely difficult in most cases to identify any of them with the very few hitherto noticed forms, the synonyms given must be regarded as at least extremely doubtful.