Proceedings of societies. 
71 
Would a specific poison have the same effect upon a cold blooded as upon a 
warm blooded animal; or was the deposit the same which infiltrated the lung 
tissue and appeared in blotches upon the skin ? 
Dr. Neligan called attention to the strong analogy that existed between this 
instance brought forward by Mr. Wright and the disease called purpura in 
badly-fed people, whose diet had been confined to any one article of food. 
FRIDAY, APRIL 18, 1856. 
R. Ball, LL.D., President, in the Chair. 
Mr. Haliday gave a sketch of the present state of knowledge of the Organiza¬ 
tion, Classification, and Natural History of the Rotifera, illustrated by Diagrams 
of some of the principal forms. The recent studies of Ley dig and Yogt, Huxley 
and Gosse, &c., were noticed; especially regarding the arrangement of the ner¬ 
vous system, misapprehended by Ehrenberg; the number and structure of the eyes, 
where they exist; the system of circulation ; the existence of distinct sexes, and 
the peculiar differences of these, which, before they were rightly appreciated, gave 
occasion to the formation of some genera and species which must now be suppressed. 
Dr. Ball exhibited living specimens of the Burrowing Urchin (Echnus lividus), 
which were sent to him from the coast of Mayo, by Mr. Richard Glennon, the well- 
known bird preserver. Dr. Ball having pointed out the peculiarities of this species, 
and stated that in 1838 he had been requested to institute experiments, with the 
view to ascertain the method by which it excavates its remarkable basins in the hard 
limestone of the Arran islands, and the still harder slates of the County of Clare, 
added, that, with the view to having the matter under his own eyes, he had imported 
a number of living specimens, and placed them at Kingstown, where he thought 
they had all perished, apparently from silt. He stated that his experiments had not 
any satisfactory result, and that to him the power exerted by this animal was still a 
mystery. He mentioned that it is found on soft slate in Cork, and on granite in 
Mayo ; and it does not burrow in either case; while in some localities it contrives 
so to modify the growth of Nullipores or rocks, as to give it the protection it obtains 
in other places by burrowing. Dr. Ball exhibited one specimen from the coast of 
Clare, in which theTmrrow, a hemispherical cavity of about two inches in diameter, 
was in a hard state; into this cavity projected a fossil, still harder than the slate, 
but probably not more silicious ; this would argue in favour of mechanical agency, 
but still a slight difference in chemical constitution may be the cause. Dr. Ball ob¬ 
served that non-excavating specimens had longer and more slender spines than those 
which excavated, and that in the colouring, varying from fine purple, through shades 
of brown, to sordid green, there appeared no rule, specimens of the different colours 
being intermixed. 
Dr. Ball exhibited the fine specimen of Scirnna umbrina, obtained many years 
ago by Dr. Joshua Harvey, of Cork, who had kindly lent it to have a model made 
of it for the collection of Irish Ichthyology, in progress in the University Museum. 
It will be recollected that of this fine fish the specimen in question is the only Irish 
example. 
FRIDAY, MAY 16, 1856. 
R. Ball, LL.D., President, in the Chair. 
The following donations to the library were acknowledged, and thanks ordered 
to be given to the donors:—“ The Flowering Plants and Ferns of Great Britain,” 
at attempt to classify them according to their Geognostic relations, by J. S. Baker, 
presented by E. Percival Wright, Esq.; “Mudie’s British Birds, 2 vols., coloured 
plates, by W. R. Tagart, Esq.; Kirby and Spence’s “ Introduction to Entomology,” 
7th edition, and Burmeister’s “ Introduction to Entomology,” by A. H. Haliday, 
Esq. V.P.; “ History of the British Diatomaceee,” by W. Smith, Esq., by the 
Author. 
