ALGOLOGICAL KOTES 7 



tub of rain-water for two consecutive years, and as brought to me 

 were perfectly pure collections. 



Chi. Grovei should be compared with Chi. globosa Snow (in 

 Bull. U. S. Fish Commission, 1902, p. 389, t. 1, f. iii.), from which 

 it is distinguished by its smaller size, the absence of a pyrenoid 

 from the chloroplast, the absence of a stigma, and the propor- 

 tionately longer cilia. 



XXII. — On Two Species of Pteromonas. 



In May, 1915, many specimens of a Pteromonas were observed 

 from some small ponds near Berkswell in Warwickshire. These 

 were carefully examined in the living state, and Dr. H. Takeda, 

 who was then working in my laboratory at Birmingham, made 

 excellent drawings of them. In September, 1915, Dr. Takeda 

 collected specimens of a Pteromonas from Devonshire, and further 

 specimens were also obtained from Ham Common in Surrey. He 

 investigated these with great care and minuteness, with the 

 result that it was found possible to discriminate between two 

 species. One species is without doubt Pteromonas angulosa 

 (Carter) Dang., first described by Carter under the name of 

 Cryi^toglena angulosa, but the other is apparently new, and since 

 our knowledge of its distinguishing features is owing to the 

 painstaking work of Dr. Takeda, it is here described as Pteromonas 

 Takedana. I had on a previous occasion confused these species 

 and figured the latter in Note XIII of this series"'' under the 

 name of Pt. angulosa. 



1. Pteromonas angulosa (Carter) Dangeard in Le Botaniste, 

 vi, 1899, p. 72; Lemm. " Beitrage zur Kenntniss der Plank- 

 tonalgen V," Ber. Deutsch. Bot. Ges. xviii, 1900, p. 93. 

 CryiHoglena angulosa Carter in Ann. and Mag. of Nat. Hist, 

 ser. 3, vol. iii, 1859, p. 18, pi. 1, fig. 18 a, b, c. Pteromonas alata 

 Cohn apud Seligo in Cohn's Beitrage zur Biologie der Pflanzen, 

 iv, 1887, p. 170, t. 3, f. 42-45. 



Long. cell, sine ala 12-14*5 /x, cum ala 15-17 [j. ; lat. cell, sine 

 ala 8-10 /x, cum ala 15-5-17/^ ; crass, cell. 8-9 /x. (Fig. 5.) 



Hah. In ponds, Berkswell, Warwickshire (G. S. West and 

 H. Takeda) ; in ponds, Ottery St. Mary, Devonshire (H. Takeda); 

 Ham Common, Surrey (W. B. Turrill). 



Carter's original description and figures of Pt. angulosa are by 

 no means accurate, but there is no question that the specimens 

 from the above-mentioned localities were referable to this species. 

 Its chief characters are to be found in the shape of the cell apart 

 from the outstanding membrane. In front view (fig. 5 A-D,/) the 

 cell is rounded-pyriform, whereas in side view (fig. 5 A-C, s) it 

 is deeply hollowed out in the middle of each side and also near 

 the posterior and anterior extremities. There is also a wide 

 toothed aperture of the external (outstanding) membrane. The 

 vertical view (fig. 5 B, e) shows the same hollowed-out nature of 



* Vide Journ. Bot., Nov., 1912, p. 330, tig. 5, A and B (p. 331.) 



