154 Proceedings of the Royal Irish Academy, 



the little bodies soon assuming the fusiform fig'ure, already accom- 

 panied by the " tracks," indispensable for their movements. 



Such is a very much epitomised abstract of the author's memoir, 

 and he sums up the conception of the Labyrinthulese as follows : — 



1. Clusters of nucleus-containing cells, increasing by division, 

 possess a certain degree of contractility, at times becoming enclosed in 

 a basic substance. 



2. These cells give off a iibrous substance, which becomes formed 

 into a rigid structure, forming reticulations and arborescent ramifica- 

 tions. 



3. The cells leave the clusters, gliding away, by manifold cir- 

 cuitous routes, to the periphery of the drop, but the Labyi-inthula- 

 cells can carry on their wandering only when supported by these 

 filamentary tracks. 



4. The wandering cells combine anew in clusters, and pass over 

 into an encysted state, each cell acquiring a firm envelope, all held 

 together by tlie common basic substance. 



5. From each cyst, after a rest of some time, four globules are 

 formed, which extremely probably become changed into young Laby- 

 rinthula-cells. 



Thus, notwithstanding the great resemblance, there are some 

 points of cUfference, of such seeming great importance as possibly to 

 forbid the present organism being subordinated to the Labyrinthuleae. 

 In the first place, the "■ spindles" are not nucleated; in the next, they 

 do not (seemingly) ever become themselves encysted, but the aggregate 

 group, matrix, colouring granules and all, become repeatedly so, and 

 that in a cellulose coat ; in the third place, Cienkowski's Labyrin- 

 thulete do not possess other colouring granules besides the sjDindles — 

 in the present form there are green and red alternating ; and, in the 

 fourth place, the former do not show contractile vacuoles, a con- 

 spicuous feature in the latter, under certain conditions ; nor did 

 Cienkowski see any organisms incepted into their mass ; and, lastly, 

 Cienkowski's forms did not evince any parasitic nature. 



The first objection seems to be the most important. Might it, 

 however, possibly be met by assuming the spindles in the present form 

 to be, as it were, all nucleus? Cienkowski offers no conjecture as to 

 any seeming or probable pui-posc of the strange wandering of the 

 spindles, save "to reach the periphery of the drop, or to get out of the 

 water;" still he says they can recede. Their object would natiu-ally 

 seem to be to transport to a distance from the piimary mass, and to 

 distribute around, the spindles, in order to lay the foundation of a 

 number of new centi'cs. Quite in a similar manner, the spindles in 

 the present form tend to pass away from the original centre, and 

 masses, accompanied indeed by a greater or less quantity of the basic 

 matrix, are sometimes left apart to form new centres. I cannot say, 

 indeed, whether or not a single spindle Avould have the power to lay 

 the foundation of a new and independent centre of growth, like to 



