Dr. J. E. Gray on Lichenella. 153 



crowded cells, forming together a nearly continuous spiral series of 

 cells on the stem ; tags indistinct. 



1. SriRALIA SPIRALIS. 



2. Spiralia unispiralis. 



^S*. unispiralis, Holdsworth, MSS. 



III. Cells with an elongated horny process on each side, and 

 disposed spirally on the articulations. 



6. CORNALIA. 



Coral arhorescent, forked ; articulations elongate, upper end with 

 a crowded spiral series of cells, each armed with an elongated horny 

 process on the side. 



1. CoRNALiA Australasia. 

 Hah. Van Diemen's Land. 



In 1850 Mr. Francis Brent sent me a Coralloid from "Western 

 Australia, which is exceedingly peculiar in its character ; for though 

 it is evidently allied to Flustra, it is so unlike, both in substance and 

 appearance, any that I have before seen, that I feel assured it must 

 form a distinct genus. 



The specimen is not in as good a state as I could vdsh, I therefore 

 placed it on one side for a time in hope that I might procure other 

 examples that might more completely illustrate its structure ; but as 

 they have not occurred, I am now induced to bring it before the 

 Society. 



It may be thus described : — 



Lichenella, 



Coral frondose, erect, branched, hard, calcareous, and brittle ; the 

 stems and branches are convex on one side, and flat or rather con- 

 cave on the other ; the stem is broad and flat ; the branches are nar- 

 row, with a more or less expanded thinner margin, which is dilated 

 at the tip into broad foliaceous expansions, which are sometimes pro- 

 liferous, giving out at the top a thin branch bearing an expanded 

 tip. 



The concave surface of the stem and branches are marked with 

 the remains of squarish cells. The expanded ends of the branches 

 are sometimes smooth on both sides ; but generally they are marked 

 externally with longitudinal grooves, and on the upper side fur- 

 nished vdth longitudinal series of thin, rather calcareous, cells, which 

 are each provided with a regularly circumscribed roundish mouth 

 closed by a thin membrane marked with a central longitudinal de- 

 pression. The smooth surface of the coral under the microscope 

 exhibits closed transverse punctated undulated cross lines. 



This coral has much more the appearance of a Lichen than of a 

 Flustra. 



