THE KNOTTED WEDGE-CORAL. 



327 



just within the wall, and thence gradually becoming thinner. The primaries 

 and secondaries equal in height and breadth ; the tertiaries much lower ; 

 all salient, the upper edge obliquely truncate, sloping down from the 

 margin inward. The two plates which form the short axis are united 

 to the columella by diverging lamina) ; but this structure appears to be 

 wanting in the others. The surfaces of all the plates are rough, with 

 scattered papillary points. 



Columella. Bent at each end towards one (the same) side ; it3 upper 

 edge thickened in irregular swellings. In some specimens it is not visible 

 from above. 



Size (of four examples). 



Animal. Unknown. 



Locality. 

 North-east coast of Ireland : deep water. 



This species resembles 8. crispus in its zig-zag folds, 

 but has more agreement with 8. mi'xtus in its general 

 characters. In its tendency to a curved form, however, 

 as well as in its pedicellate character, and especially in 

 the presence of a well- formed basal area, which appears 

 to have been a point of adhesion, it displays so much 

 affinity with Ceratotrochus (according to the diagnosis of 

 M. Milne Edwards) that I was at first disposed to assign 

 it to that genus. 



The four specimens that I have above described have 

 been entrusted to me by my kind friend, Dr. E. Perceval 

 Wright, of the Dublin University, with whose name I have 

 honoured the species. They w T ere dredged by G. C. Hynd- 

 man, Esq., among shell sand, from a turbot bank off the 

 coast of Antrim, in 1852. 



I have introduced the tiny form into this work, believing 

 it to be an existing, and not a fossil species. Professor 



