1867.] DR. J. E. GRAY ON CORALLIUM JOHNSONI. 12') 



of shell attached with cement, giving the whole the appearance of 

 the true bark, the knots representing the polype-prominences, — and 

 so well done that it deceived an intelHgent collector. 



The same collector brought me a specimen of a coil which had 

 some of the natural bark on the middle part of the specimen ; but 

 the narrow lower end was covered with strips of the bark wound 

 round it in a spiral manner, so that the bark appeared to cover the 

 base of the coil nearly to the end ; but when closely examined, the 

 edges of the strips were distinctly visible. 



I have seen another specimen in which the coil of spicules was 

 scattered with small pieces of bark, generally containing a single 

 polype, but in two or three cases two polype-cells ; and on the tips 

 of some of the spicules were affixed in the same manner, with cement, 

 a piece of bark containing a polype ; in one or two instances two 

 such pieces were on the same spicule. 



6. Additional Note on CoraUium johnsoni. 

 By Dr. J. E. Gray, F.R.S., Y.P.Z.S., &c. 



In the Proceedings of this Society for 1860 (p. 393, Radiata, 

 pi. XVIII.) I described and figured a new species of Coral, which 

 had been discovered by Mr. James Yate Johnson at Madeira, under 

 the name of CoraUium johnsoni. 



The Rev. Henry H. Higgins, an active trustee of the Liverpool 

 Free Museum, has most kindly sent to me for examination a small 

 specimen of a Coral received from Mr. Johnson, from Madeira, 

 which is evidently the same species, showing the coral in its young 

 state. As the specimen is very unlike the old part of the coral 

 that I figured, and also very dissimilar to the young branches of 

 the CoraUium ruhrum of the Mediterranean, I have had the figure 

 that Mr. Higgins most kindly sent with the specimen reproduced 

 (see fig., p. 126). 



The great peculiarity of this coral is that the polypes all arise 

 from one surface, and I have no doubt that it grows out horizontally 

 from the rocks, and that they arise from the upper surface of the 

 branches. 



The polypes also differ from those of the CoraUium ruhrum of the 

 Mediterranean in being very prominent from the bark, and of an 

 ovate subcylindrical form, marked with longitudinal grooves, which 

 are most distinct near the opening of the polype-cell. 



I have little doubt that the above is the true explanation of the 

 specimen ; but Mr. Johnson, who sent the specimen to Liverpool, 

 labelled it "a zoophyte parasitic on a dead coral." 



The genus CoraUium should be divided into three, as follows : — 



I. CORALLIUM. 



The polypes slightly elevated from the bark, and scattered on all 

 sides of the branches. 



