BY G. I. PLAYFAIR. 525 



Genus 8 p o n d y l o m o r u m Ehr. 

 Spondylomorum quaternarium Eh J. 



Ehrenberg, Beob, zweier generisch. neuei' Fornien d. Frilhlings- 

 gewassers bei Berlin, Monatsber. d. Berl, Acad. d. Wissensch., 

 1848. CJ\ Stein, /.c, T. xviii., f. 30-34. 8yn., EnrkiRia cornuta 

 W. & G. S. West, Frw. Alg. Biuma, p.L>28, PL xii., f.19-21: Uva 

 Casinoensis Playf., Biol. Richm. R., p.l08, PI. ii., f.l3. 



This flagellate seems to be very little known; it is not men- 

 tioned either by Chodat in Alg. vertesde la Suisse, 1902; nor by 

 G. S. West in Br. Frw. Algae, 1904. Lemmermann reports it 

 from a single locality in Sweden, but it is not included in Bach- 

 mann's Das Phytoplankton des Siisswassers, 1911. In my former 

 paper, I had not the assistance of Stein's excellent illustrations; 

 also the figure and description of this organism published in the 

 Micrographic Dictionary, p.721, PI. 3, f.23, are entirely incorrect 

 and misleading. The figure here given agrees almost exactly 

 with that by Stein, I.e., f.30, save that the stigma is above, not 

 below% the centre. 



The coenobia are generally oblong, consisting of rings of four 

 cells, arranged one above another. They easily break up either 

 longitudinally or transversely; in the latter case, the resulting 

 coenobia are often hemispherical or rosette-shaped. The cells, 

 originally globose, very soon become broadly oval or ovate; the 

 hiembrane is very delicate, and, by reason of their very rapid 

 movement through the water, it is generally drawn out at the 

 back into a short pointed sac, at first very indistinctly outlined. 

 Later, however, it becomes stouter and more evident. The chlo- 

 roplast is cup-shaped, generally without a pyrenoid; there is a 

 central nucleus, two apical contractile vacuoles, and a stigma, 

 median or a little above or below the midline. The internal 

 details, however, are not easily seen, as the cytoplasm is gener- 

 ally very dense. In a zooid which became detached from a 

 coenobium, I was able to see distinctly that there are two un- 

 usually long apical flagella. Noted from at least four different 

 spots round Lismore. 



Ccenob. long. 28-40, lat. 22-27: cell. long. 10-20, lat. 6-12/x. 



