ACOTYLEDONS, ALG/E. 



HAB. Rocks in the Highland rivulets, near the foot of the mountains, 

 frequent, Lightf. 



Frond oval, an inch or more in diameter, olive green, gelatinoso-c.o- 

 riaceous, plicato-lobate, smooth, at length spreading into an ulva- 

 like membrane, 4 5 inches in diameter. Filaments flexuose, com- 

 pact and intricate, nearly equal at first, at length momliform. Ag. 



2. ALCYONIDIUM. Lamour. 



Capsules graniferous, imbedded in a fleshy or gelatinous sub- 

 stance. Frofldsubcylindrical, lobed; substance between spongy 

 and gelatinous. 



1 . A. diaphanum, subgelatinous pale yellowish pellucid somewhat 

 cylindrical with numerous branches and lobes of various sizes. 

 Ag. p. *131. Ulva diaphana, E. B. t. 263. Alcyoninm ge- 

 latinosum, Linn. 



HAB. Cast on shore in the Orkney islands, Mr. P. Neill. 



Has very much the appearance of animal substance. 



3. RIVULARIA. 



Filaments arising from a common base, continuous, anuulated 

 within, of an olive or dark green colour, globular. -Filaments 

 (resembling those of Oscillatoria) simple, continuous, annu- 

 lated within," having a globule at one extremity, at the other 

 terminating in a long diaphanous point. Their mode of in- 

 crease is hitherto unknown. 



1. R. ? tuberiformis, frond irregularly globose inflated folded oli- 

 vaceous brown smooth; globules of the filaments in the external 

 surface of the frond. E. B. t. 1956. Tremella difformis, 

 Lig/itf. p. 900. 



HAB. On Conferva and other marine substances, and on the rocks at 

 low water, Lightf. Abundant at Ulva, Staffa, and lona, in such 

 situations. 



An inch or more in diameter, coriaceo-gelatinous, hollow. The fila- 

 ments tapering from the globular extremity, which is in the surface, 

 internally, to long attenuated points. 



2. R. atra, fronds hemispherical solitary hard shining blackish 

 green, filaments densely crowded fasciculated at the base pel- 

 lucid green. Ag. p. 130. E. B. 1. 1798. Tremella hcmi- 

 sphterica, Linn., Lightf. p. 900. 



HAB. Marine rocks, not uncommon. 

 Minute, appearing black. 



4. CH^ETOPHORA. 



Filaments arising from a common base, jointed. Gemma scat- 

 tered among the mass of the frond. Frond very gelatinous, 

 palmate, globose, or filiform. Filaments (like those of a Con- 

 ferva] branched, jointed, gradually tapering, produced beyond 

 the surface of the fro?id, into long, diaphanous pointy. Gem- 



