208 Proceedings of the Royal Irish Academy. 



place in a downward clii-ection — a supposition which, perhaps would be 

 strengthened by the absence of ambulacra on the flattened side. I am 

 free to confess, however, that this solution is not satisfactoiy, for it 

 would be a matter of no little diificulty to arrange the surroundings so 

 as to produce the given result, and hence I am faia to keep clear of the 

 cloud-begirt regions of hypothesis, and limit myseK to the simple 

 record of facts. 



MaKormed specimens of Echini have been described by the fol- 

 lowing : — 



Philijjpi, " Weigmann's Archiv fur ISTatui'geschichte, 1837." I 

 have not been able to consult this paper, as the volume of this 

 Archiv for 1837 is not in. any of the Dublin libraries. 



Kinahan and Du j^oyer, " Proceedings of the Dublin Xatui'al His- 

 tory Society," vol. ii., 1857. The specimen seems to combine the pores 

 ancl tubercles of Strong yloeentrotus lividus, with the actinal system of 

 Ecliinus esculentus. 



T.H. Stewart, ''Annals and llagazine of Xatiu'al History, 3rd 

 series, Yol. v., 1860." The malformation is chiefly in the abactinal 

 system, the corona being but slightly altered. 



Donitz, "Eeichert und Du Bois'Pteymond's Archiv, 1866." The 

 malfoiTnation consists in the almost total disappearance of one of the 

 five interambulacra, and a corresponding change in shape of the corona. 



