PALMELLACE.E. 



became more dense, and the reticulated arrangements lost, or rather, 

 perhaps, more properly speaking, the interspaces become clothed with 

 chlorophyll granules. At first glance this might be mistaken, under a 

 low power, for that small form of Eremosphtera viridis, which origi- 

 nates when the individuals of the ordinary large form produce simul- 

 taneously four, in place of two daughter cells; but the evident elliptic 

 figure and the thickened poles, as well as the different arrangement of 

 the chlorophyll contents, would, on closer inspection, at once distinguish 

 them. Mr. Archer has drawn attention to the seemingly curious very 

 great expansion of the wall of the mother-cell, almost looking as if in 

 anticipation, rather than as in consequence of the growth of a young 

 ' brood ' of two, four, eight, or sixteen daughter-cells, so much so that 

 it almost had the aspect of a fresh growth, rather than that of a mere 

 swelling up of the old membrane." Quart. Journ. Micr. Sci., 1877, 

 p. 105. 



Oocystis setigera. Archer, in Quart. Journ. Micr. Sci., 1877, p. 194. 



We are unable to give any description of this species which, 

 as far as we are aware, bears only a manuscript name. Neither 

 are we able to give figures of either species, although we hope 

 to do so hereafter. 



GENUS 20. DIMORPHOCOCCU8. Br. (1849.) 

 Cells united in fours on very short branches, dissimilar, the 

 two intermediate contiguous oblique, obtuse ovate, the two 

 lateral, opposite and separate from each other, lunate ; families 

 free swimming, in botryoid clusters. 



This genus is allied to Dictyospkasrium, next to which it should have 

 been placed. 



Dimorpho coccus lunatus. Br.Alj. Uni.p. 44. 



Green, apices of the cells hyaline. 

 SIZE. Cells longitudinal diam. '01- '02 mm. 

 Rabh. Alg. iii. p. 36. Archer, Quart. Journ. Micr. Sci., 

 1872, pp. 195, 197. 



Floating in pools. N. Wales. 



We have been unable to make a successful drawing from the 

 specimen we possess of this Alga, as we have not seen it living. Mr. 

 Archer, on reporting upon its occurrence in Ireland, criticised the only 

 figure extant (in Eabenhorst's Alg. Eur.) in the following terms : " The 

 upper or outermost cells do not, as they are made to seem, or as the 

 original description might lead one to infer, stand above the larger and 

 lower (inner) cells as upon a common stipes, but the former grow off 

 from the latter, and remain joined thereto by a short pedicle. The inner 

 eels are broadly reniform, and two stand opposite to each other at the 

 apex of the supporting stipes, so as to present a lunate figure, and from 

 the lower part of the sinus made by these it is that the pedicle of each 

 of the pair of secondary, more or less reniform, but unequally lobed, 

 cells (one from each lower cell) starts, the smaller lobes of these latter 

 overlapping each other, and appearing, in a crowded cluster, like one 

 cell, only of smaller dimensions, concentrically posed above the lower 



