NOTICE OF THE GENUS TETRAPEDTA, ETC. 365 



somewhat convex on their lower margins ; the other opposite 

 margins of the cell, that is, the upper margins of the seg- 

 ments, very slightly concave at the middle, someAvhat raised 

 towards the sub-acute minutely apiculate outer angles ,* in 

 side view oblong, constricted at the middle, ends rounded. 

 In moor pools, Counties Dublin, Wicklow, and Galway. 

 Figs 11, 12, 13. Diameter of largest cell met with (from 

 angle to angle in both directions equal) from about ir-iiru" to 

 say one third or even one half smaller. 



In venturing to associate Professor Keinsch's name with 

 this species, I may take the opportunity to express the great 

 pleasure with which I have availed myself of his interesting 

 papers and correspondence, though unable to concur with 

 certain of his views ; and I would also use the occasion to 

 thank him highly for the valuable and much esteemed favour 

 conferred by his having been so good as to forward me copies 

 of his memoirs. 



Tetrapedia setigera, no v. sp. 

 Cells triangular, each lateral margin somewhat deeply 

 excavated by a broad rounded sinus, dividing the cell into 

 three lobes rounded at the ends, and each terminated by a 

 very delicate straight bristle, in length about equal to the 

 diameter of the cell ; in side view oblong, somewhat inflated 

 at the middle at each side, ends rounded, and each seen 

 tipped by the bristle. 



In moor pools. Counties Dublin, Wicklow, and Galway. 

 Figs. 14, 15, 16, 17. Diameter of cell (without bristles) 

 about ^yVfr to -j-+W' ^'o^n end to end, including the bristles 

 about -r3Vo to ttV o"- 



Of the genus Tetrapedia and the two original species 

 therein included by him, Professor Reinsch has furnished 

 in his Avork only the diagnosis (previously herein repeated), 

 and the explanation of the figures, whence we can draw in- 

 formation or gain a knowledge of his views. His figures are 

 given in the original upon a very large scale indeed, and 

 hence probably calculated to induce misconception as to the 

 actually very minute size of the forms ; the majority of them 

 are here repioduced upon a scale of some 400 diameters, and 

 the best " explanation of the figures" that can accompany 

 them will be simply a direct translation, though not taken in 

 jjrecisely the same order, from the original : 



Tetrapedia gothica (Reinsch). 

 Fig. 1. A simple developed cell, Avhose lateral margins 

 present the indication of division. 



' See uote, ante. 



