Marine Algcc of the Orkney Islands. 319 



Family.— HILDENBEANDTIACE.E. 



HILDENBRANDTIA, Naido. 



113. Hildenbrandtia rosea, Kiitz. {Hildcnbraiidtia rubra, Meneg. ) 



On pebbles and smooth stones in shallow pools, generally at about 

 half-tide level. All the year. Fruit in autumn and winter. 



Family— WRAXGELIACEyE. 



CHANTRANSIA, Fries. 



114. Chantransia Daviesii (Dillw.), Thur, {CccUitJiamnion Davicsii, 



Lyngb.) 



Epiphytic on various Algpe at Skaill Bay, West Mainland, and 

 Kirkwall Bay. Specimens named both by Professor Harvey and 

 Mr Batters. Annual. Summer and autumn. 



115. Chantransia secundata (Lyngb.), Thur. (Callithamnion sccun- 



datum, J. Ag. ) 



Epiphytic on Algae from about half-tide level to low-water mark. 

 Usually uncovered by the tide, and exposed to the light for some 

 hours daily. Annual. ]\Iay to September. Fruit in summer. 

 Occurs at Skaill, West Mainland, and named by Harvey; at 

 Broch in Rousay, epiphytic on Alaria esculenta (G. W. T.); 

 corroborated by E. M. Holmes. 



116. Chantransia virgatiila, Thm-. {Callithamnimi virgcdulum, Harv.) 

 Usually epiphytic on Ceramiura ruhrum in pools between tide 



marks. Annual. Summer. Found in Kirkwall Bay by ]\Ir 

 Pollexfen ; named by Mr Batters. 



MONOSPORA, Sol. 



117. Monospora pedicellata {Eng. Bat), Sol. {Callithamnion pedicel- 



latum, Ag. ) 



Dredged in Kirkwall Bay (Pollexfen) ; dredged in Calf Sound, 

 7 fathoms, stony and coral bottom (M'Bain), Annual. Summer. 



SPERMOTHAMNION, Aresch. 



118. Spermothamnion Tvirneri (ilert. ), Aresch. (Callithamnion TurneH 



(Dillw.), Ag.) 



Epiphytic on small Algae near low-water mark; always sub- 

 merged. Annual. May to September. Fruit in summer. Occurs 

 at Sanday in pools ; also in Kirkwall Bay ; and at vSkaill, West 

 Mainland. The variety rej)ens also occurs. 



Family.— HELMINTHOCLADIACEiE. 



HELMINTHORA, J. Ag. 



119. Helminthora divaricata (Ag.), J. Ag. {Diulrcsimya divaricata, 



J. Ag.) 



On rocks and stones, or epijDhytic on Algae, near low-water mark, 

 and in deep water ; sandy and coral bottoms. Annual. Summer 

 and autumn. Very fine at Skaill, West Mainland. 



