88 PllOCEEDINGS 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 Virgularia, 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. 



