APPENDIX. 381 



orbicular or renifonn folds, one over another, and attached 

 as it were to a common centre. The substance is very- 

 thin and transparent, and the interspaces are much broader 

 than the elliptical spaces. 



2. a. cellulosa. 



Hab. — Bass Strait, 45 fathoms. 



Not distinguishable from a Mediterranean specimen. 



3. R. ctenostoma, n. sp. 



Frond umbOicate, irregularly infundibidiform, spaces 

 elongated, narrow, margins subdenticulate ; interspaces as 

 wide as the spaces. Mouth of cells tubular, projecting ; 

 with six or seven unequal acute expanding teeth. 



Hab. — Bass Strait, 45 fathoms. 



A very distinct and beautiful species. The frond is about 

 half an inch wide, and though really umbUicate and sub- 

 infiindibuhform, does not at first sight appear so, being 

 much more expanded on one side of the centre than on the 

 other. 



19. EscHAUA, Ray. 



1. E. lichenoides, M. Edwards. Mem. sur les Eschares. 

 Ann. d. S. N. t. vi. p. 31. pi. 2. fig. 3. 



Hab. — Australian Sea, probably Bass Strait. (It also 

 occurs in Algoa Bay.) 



20. DiACHORis, n. gen. Tab. i. fig. 10 — 12. 



Cells separate, each connected with six others by short 

 tubes ; disposed in a horizontal plane, and forming a con- 

 tinuous irregular frond ; free, or partially adnate. 



The mode of arrangement and interconnexion of the 

 cells in this genus is remarkable, and highly interesting. It 

 represents, in fact, a dissected Flustra or, Membranipora. 

 The cells are disposed in linear parallel series, and those of 

 two contiguous series are alternate with respect to each 



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