662 Haddon and Shackleton — A Revision oj the British Actinice. 



Jourdan has recently (1890, p. 175) identified a form dredged by the Prince 

 of Monaco (? either from the Bay of Biscay or off the Azores) as '■'• Palythoa sulcata 

 Gosse." 



Zoanthus alderi, Grosse. 



Zoanthus alderi : 



Gosse, 1860, Brit. Sea Anemones, p. 305, pi. ix., fig. 8 ; pi. xii., fig. 5. Gray, 1867, Proc. Zool. 

 Soc, p. 234. Pennington, 1885, Brit. Zooph., p. 183. Alder, Trans. Tyneside Nat. Field 

 Club, V. 



Zoanthus {Rhyzantlms) alderi : 



Andres, 1884, Le Attinie, p. 328. 



Form. — " Polyp inversely conical, the summit being two or more times as broad 

 as the base ; summit (in the button state) swelling, flat, depressed in the centre, with 

 many (about twenty ?) radiating striae, indicating the marginal teeth. Surface 

 smooth, without any investment of sand, but marked throughout with close-set, 

 transverse, or annular wrinkles. Coenenchyme narrow, smooth, irregularly 

 branching, free from sand." 



Colour. — Opaque, milk-white. 



Dimensions. — Height of column about two lines (4 mm.) ; greatest diameter 

 about half a line (1 mm.). 



Habitat. — Northumberland ; under-surface of a stone, at extreme low water, 

 near the " Bear's Rock," Cullercoats (Alder). 



This species has not been met with since its first discovery by J. Alder in 1857. 

 Gosse says: "There were about a dozen polyps in the colony, all of the same 

 size, which seems to be good evidence that they had attained adult dimensions." 

 Alder adds that he has " searched for it several times without success." We 

 cannot help regarding this as an immature form. 



No representative of the genus Zoantha, as determined by anatomical investi- 

 gation, is known to occur in the extra-tropical portion of the North Atlantic. 



Until the anatomy of ^^ Z. ruhricornis^'' '■'■ Z. sulcatus,''^ and ^^ Z. alderi'''' is 

 investigated it will be impossible to tell the genus, let alone the species. The 

 same criticism applies to the identification of nearly all the Zoanthese. 



