QUADRTJLA. 129 



Genus 26. aUADRULA F. E. Sclmlze, 1875. 



Difflugia (pars) WALLICH in Ann. Nat. Hist. (3) XII (1863), 



p. 458. 

 Quadrula F. E. SCHULZE in Arch, mikr. Anat. XI, 2 (1875), 



p. 329. 



Test pyriform, sub-globose, or discoid, consisting of 

 a homogeneous cliitinous film, with quadrangular plates 

 of siliceous or calcareous substance superimposed, the 

 plates generally lying in oblique series, their edges 

 touching (rarely overlapping) and sometimes loosely 

 arranged. Protoplasm and pseudopodia not differing 

 from those of Dijfftugia ; uninuclear. 



1. Quadrula symmetrica (Wallich) F. E. Sclmlze. 

 (Plate XXIX, figs. 1-3; and fig. 101 in text.) 



Difflugia proteiformis var. symmetrica WALLICH in Ann. Nat. 

 Hist. (3) XII (1863), p. 458, t, viii, f. 16. 



Difflugia pyriformis var. symmetrica WALLICH in Ann. Nat. 

 Hist. (3) XII (1863), p. 467; and op. cit. (3) XIII (1864), 

 p. 232, t. xvi, f. 26. 



Difflugia symmetrica WALLICH in Ann. Nat. Hist. (5) XVI 

 '(1885), p. 463, f. 1. 



Difflugia assulata EHRENBERG in Abh. Akad. Wiss. Berlin, 

 1871 (1872), pp. 246, 249, t. ii, ff. 4, 5. 



Difflugia carolinensis EHRENBERG in Abh. Akad. Wiss. 

 Berlin, 1871 (1872), pp. 246, 250, 274, t. iii, f. 14. 



Difflugia leptolepis EHRENBERG in Abh. Akad. Wiss. Berlin, 

 1871 (1872), pp.. 254, 264, 274, t. iii, f. 15. 



Quadrula symmetrica F. E. SCHULZE in Arch. mikr. Anat. 

 XI, 2 (1875), p. 329, t. xviii, ff. 1-6 ; LEIDY (pars) in Pr. 

 Acad. Philad. 1875, p. 415; op. cit. 1879, p. 162; and 

 Freshw. Khiz. N. Amer. (1879), p. 143, t. xxiv, ff. 20-24; 

 ARCHER in Q. Jrn. Micr. Sci. (n.s.) XVII (1877), p. 112, 

 t. viii, f. 6; and in Jrn. Dublin Micr. Club, III, 2 (1877), 

 pp. 128, 230, t. viii, f. 6; BUTSCHLI in Bronn's Thier- 

 Keichs, I, 1 (1880), t. ii, f. 12 ; LANESSAN in Eev. internat. 

 Sci. VI (1880), p. 9, f. 7; and Traite Zool., Prot. (1882), 

 p. 52, f. 43; GRUBER in Zeits. wiss. Zool. XXXVI, 1 

 (1881), p. 106, t. iv, f. 1 ; HITCHCOCK Synops. Freshw. 

 Rhiz. (1881), p. 19 ; TARANEK in Sitzber. bohm. Ges. 



VOL. II. 9 



