88 
PROCEEDINGS OF SOCIETIES. 
umbrella, instead of being fixed to the ground; in others (sarsia), this polype 
becomes compound, rendering the resemblance still more complete; and in some 
(diphyes and its allies), we have an organism closely resembling, in many parti¬ 
culars, a very compound hydroid attached to a bell-like locomotive. He was 
inclined, then, to consider the Hydroid Zoophyte homologous with the depending 
stomach and mouth of the Acaleph. 
Next to the sertularians, Dr. Thomson thought himself justified, with all 
deference to Agassiz’s contrary opinion, in placing the graptolites, a set of extinct 
zoophytes, highly characteristic of the earliest palaeozoic formations. In this tribe 
the root-fastening is usually wanting, the polypidom having apparently stood 
upright, with its base immersed in soft mud. The horny covering is free, as in the 
sertularians, and so are, in many cases, the opening of the cells, although in some 
the edge is prolonged into a lax tubular orifice, as if at that point there had been an 
union between the body of the animal and the case. The whole polypidom was 
strengthened by a delicate horny rod passing up along the side of the common tube. 
In some mature specimens of several species, the lecturer had observed a minute 
roughened aperture towards the base of each cell, at which point something had . 
apparently been broken off, possibly a vesicle. This last series naturally fills up a 
blank between the sertularians and the next set, the asteroids. In this latter 
series the external tube is wanting; the whole strengthening material being 
concentrated in an internal calcareous or horny support, and the polyps continuous, 
with an external fleshy cortical substance, which incrusts the support on all sides, 
being only retractile into cavities in this crust. This order is represented in this 
country by the beautiful Yirgularia, Pennatula, and Gorgonia. After a short ex¬ 
position of the Helianthoid tribe, and the formation of coral, the lecturer concluded 
with a few general remarks on the phenomena of the so-called alternations of 
generation. 
KILKENNY LITERARY AND SCIENTIFIC INSTITUTION. 
MAY 13, 1855. 
Dr. Cane in the Chair. 
Mr. Robertson read the following paper, entitled 
NOTES ON THE EFFECTS OF THE LATE FROST. 
Since the weather of a district forms a part of its history, but more especially of 
its natural history, I have thrown together a few notes on the late frost, which 
was the most severe that we have known for many years, and remarkably injurious 
to evergreens. Some account of its effects may, therefore, be useful, and not 
unacceptable, to persons who delight in planting, as it is of importance to every 
planter who wishes to escape the mortification of losing, in a few days, the labour 
and hopes of many years, to make himself acquainted with such shrubs as are most 
likely to withstand the ravages of an unusually severe winter. 
In many countries, historians and naturalists have recorded the occurrence of 
remarkable phenomena connected with the climate of their several localities, so 
that we have an ample field for reference and comparison. On referring to that 
most pleasing little work, White’s “ Natural History of Selborne,” I find that its 
observant author records the severity of three hard frosts which occurred in the 
years 1768, 1776, and 1784 ; I also learn, that the evergreens which suffered most 
in England in those years are the same which have been destroyed here in the late 
frost, to which, however, a long list of more recently-introduced plants must be 
added. According to White’s account, the severest frost occurred early in the 
month of January in the years 1768 and 1776, and in the month of December in 
1784; I need hardly remind my hearers that February was far advanced when the 
late frost was most severe with us, and I find, on consulting a table kept by Mr. 
