Royal Irish Academy. 6? 



always added to the point. The granules so attached, becoming 

 nourished by the contents of the vessel, and the spaces between 

 them, are in a short time obliterated by the fibre acquiring a defined 

 border which completes its development. 



This act is the one observed in the formation of the fi])re of all 

 vessels, but the arrangement of the granules differs so as to consti- 

 tute the several varieties. In the annular vessel the granules attach 

 themselves horizontally, forming rings. In the spiral they become 

 inclined, and by continuing this direction around the interior of the 

 membranous tube, the peculiar character of the vessel is obtained. 

 In the reticulated, each division or branch of the fibre or granule 

 becomes enlarged in the line, and forms the starting-place for the 

 fresh direction of the fibre. In the dotted and scalariform vessels, 

 the fibres become so reticulated as to have portions of the outer 

 membrane of the vessel without any deposit within ; and this spot, 

 so left, constitutes the dot or linear marking seen in these vessels. 



This dot is plain in all such vessels, excepting those found in 

 woody exogens, where it possesses (from a slight diff^erence in 

 structure) a central mark analogous to that on the woody tissue of 

 coniferous plants with which Mr. Quekett considers it identical, but 

 only of a smaller size. The paper was illustrated with numerous 

 diagrams, which gave representations of the successive stages of the 

 minute process Mr. Quekett had observed. 



ROYAL IRISH ACADEMY. 



November 11, 1839. — Mr. Ball read a paper **on the Bolina 

 Hihernica," by Robert Patterson, Esq., Member of the Natural 

 History Society of Belfast. 



In a note appended to his paper on the Cydippe Pomi/ormis, 

 (Trans. R. I. A., vol. xix., part 1, page 96,) the author had men- 

 tioned the occurrence on the Irish coast of a species of ciliograde, 

 which he had named provisionally Bolina Hibernica. A large num- 

 ber hav.'ng been taken in the bay of Bangor, county of Down, on 

 the 11th of July, 1839, the drawings now brought forward were 

 executed from living specimens. 



The movement of this Beroe was stated to be less vivacious than 

 that of the Cydippe Pomiformis, and it is much more susceptible of 

 external injury. The long-continued action of certain portions of 

 the cilia, after the animal was broken to pieces, was mentioned ; 

 the variety of aspect presented by the tentacula described ; and the 

 situation of certain whitish cords or vessels minutely detailed. The 

 lobes of the mouth were shown by the figures not to occupy more 



p 2 



