APPENDIX. 375 



4. B.flexilis, n. sp. 



Cells obliquely truncated above with a short spine on the 

 outer angle ; opening large, suboval, with an obtuse angle 

 outwardly ; margin slightly thickened, wholly unarmed. 



Hab. — Off Cumberland Islands, 27 fathoms^ fine grey 

 mud. 



Of a light grey colour : grows in large loose tufts, com- 

 posed of long forked ascending branches. It is a very 

 peculiar species, and some difficulty has been found in 

 finding it a place. In the opening of the mouth, and the 

 external short spine, it is a Cellaria ; and in the colour and 

 want of distinct articulation, it approaches Acamarchis ; 

 whilst in the form of the cell, and their mode of mutual 

 connexion, it is a Bicellaria : it differs from all other species 

 of that genus, however, in the absence of any long spines, 

 and in general habit. Were it not referred to that genus, 

 it would probably constitute the type of a distinct one. A 

 curious little trident-like organ is visible in the narrow part 

 of some cells. 



15. Acamarchis, Lamouroux. 



Char. (B.) — Cells elliptical,* closely contiguous ; open- 

 ing very large, margin simple, not tliickened. Avicularia 

 not always present, Hke birds' heads. 



To which may be added, that the species are frequently 

 coloured, red or bluish. 



1. ^. neritina. Lamouroux. 



Hab. — Bio de Janiero. Broken Bay, N. S. Wales. 



This species appears to be one of the most generally 

 distributed of the Polyzoa ; it occurs in nearly every lati- 

 tude in both hemispheres. 



(?) 2. A. tridentata, Krauss. CoraU. d. Sudsee, p. 3. 



fig. 2. 



Hab.— Bass Strait (?) 



* Viewed posteriorly. 



