Vlll SYNOPSIS OF THE 



* Frond filiform, articulated. 

 XLVI. Corallina. Frond pinnated. Ceramidia terminal, simple. 



XLVII. Jania. Frond (in the Brit, species) dicliotomous. Ceramidia tipped with 

 two horn-like ramnli. 



* * Frond crustaceous or foliaceous, not articulated. 

 v XL VIII. Melobesia. Opake, stony ; crustaceous, foliaceous, or shrubby. 

 XLIX. ? Hildenbrandtia. Cartilaginous (not stony), incrusting rocks. 



L.? Hapalidium (Kiitz.). Minute, crustaceo-membranaceous, hyaline, composed 

 of a single stratum of cells radiating from a centre. 



Order 10. DelesseriacEjE. Rosy or purple-red or blood-red seaweeds, 

 with a leafy, rarely filiform, areolated, inarticulate frond, composed of 

 polygonal cells. Leaves delicately membranaceous. Fructification 

 double : 1 . Conceptacles (coccidia) external or half-immersed, hemisphe- 

 rical, usually imperforate, containing, beneath a membranous pericarp, 

 a tuft of filaments, whose cells are finally changed into spores. 2. Tetra- 

 spores in distinctly defined sori, either scattered or confined to proper 

 leaflets (sporophylla). 



LI. Delesseria. Frond leafy, of definite form, with a percurrent midrib. 



LII. Nitophyllum. Frond leafy, irregularly lobed, without midrib. 



LIII. Plocamium. Frond linear, compressed, distichously much branched; ra- 

 muli pectinate, acute. 



Order 11. Ehodymeniace^:. Purplish or blood-red seaweeds, with an ex- 

 panded or filiform, inarticulate frond, composed of polygonal cells; oc- 

 casionally traversed by a fibroso-cellular axis. Superficial cells minute, 

 irregularly packed, or {rarely) disposed in excentric filaments. Fructi- 

 fication double: 1. Conceptacles (coccidia) external or half -immersed, 

 globose or hemispherical, imperforate, containing, beneath a thick pericarp, 

 a mass of spores, on a central placenta. 2. Tetraspores either dis- 

 persed indefinitely, or forming cloud-like patclies. 



* Frond fiat, leaf -like, dicliotomous, or palmate. 

 LIV. ? Stenogramme. Conceptacles linear, rib-like. (Sori definite.) 

 LV. Ehodymenia. Conceptacles hemispherical, scattered. 



* * Frond compressed or terete, shrubby, much branched. 

 LVI. SpHjErococcus. Frond linear, two-edged, distichous, traversed by an 

 obscure midrib. 



LVII. Gracilaria. Frond filiform (rarely compressed or flat), irregularly 

 branched ; the central cells very large. 



LVIII. Hypnea. Frond filiform, irregularly branched, traversed by a fibro- 

 cellular axis. 



Order 12. CRYPTONEMiACEiE. Purplish or rose-red seaweeds, with a fili- 

 form or (rarely) expanded, gelatinous or cartilaginous frond, composed, 

 wholly or in part, of cylindrical cells, connected together into threads or 

 filaments. Axis formed of vertical, periphery of horizontally excentric 

 filaments. Fructification double: 1. Conceptacles (favellidia), globose 

 masses of spores immersed in the frond, or in swellings of the branches. 

 2. Tetraspores variously dispersed. 

 Sub-order 1. CoccocarpejE. Frond solid, dense, cartilaginous, or horny. 

 Favellidia in semi-external tubercles or swellings of the frond. 



