DR. G. P. BIDDER ON SYNCBYPTA SPONGIARUM. 305 



Syncrypta spongiarum, nova *. By G. P. Bidder, Sc.D., F.L.S. 



(With Text^figures.) 



[Read 6th May, 1920.] 



In discussing the natural food of Grantia compressa (1895 tj P- 31, cf. ante, 

 p. 300), I wrote: — "In another specimen there are lying freely in the 

 chambers several specimens of what appears to be an alga, one sphere of 

 four cells, one probably of sixteen ; also lying inside the collars of different 

 collar-cells are several isolated spheres, of about the same size as the 

 individual cells of the larger spheres and similarly stained." My rough 

 MS. sketch of the sphere inside the collar (fig. E) when scaled by the 

 dimensions of the collar-cell gives the diameter of the "isolated sphere" 

 as 1^ jx. The "sphere of four cells'' (fig. A), assuming that each "cell" 

 is 1'5/iA,. has an external diameter of 7 ft,. (See Text-figures, p. 308.) 



Our knowledge of this organism (but under the title of sperm-morulse) 

 has been greatly increased by Dendy's beautiful drawings (1914, pi. 26). 

 Mr. Gratenby's paper, read at the Linnean Society on December 11th, 1919, 

 gave a totally different account of the spermatozoa in Grantia, which 

 in the subsequent discussion was accepted by Professor Dendy ; we may 

 therefore consider the explanation of the organisms as sperm-morulas to be 

 withdrawn. Their identity with the objects seen by me in 1895 is shown 

 by their situation, their binary multiplication and coherence, and their 

 dimensions. The external diameters of the eight-celled stages of Dendy's 

 fig. 83 and fig. 86 are 6'4 and 7 - 0/a respectively, the diameters of the 

 spherules composing them being 2 - l and 2'ip,; while the diameter of 

 the spherules in fig. 90 (16 cells) is 1*3 /a, and the external diameter of the 

 16-celled stage in fig. 92 reaches 10 /x. The sub-conical elements in his 

 fig. 89, each bearing two spots (these are shown in four out of the six monads, 

 see fig. H, infra, p. 308), are extremely like the published figures of Flagel- 

 lata, and there seems no reason for any further hesitation in assigning the 

 organism to this group. I understand from botanical friends that I shall not 

 find in the literature a specific name for this organism, and that of spon- 

 giarum seems to suit the circumstances. 



Since sending in this manuscript, I have observed at Plymouth that the 



* Colonic globosae, 3-1 2/t diam. extern., e cellulis 4-8-16 aiireo-brunneis in gummi 

 communi iramersis composite, interdum cellulas solitaria?, G"5-3/* diam., punctis (ocellis 

 dictis) binis et pyrenoideo niagno instructs. 



llab. in Grantia compressa loculis flagellars in portu "Plymouth," mensibus Dec, Jan., 

 Apr. (et Jul. ?). In mari mediterraneo colonic etiam e cellulis 32 composite obveniunt. 



{ For references to works quoted in this paper, see p. 325. 



