QUADRULA. 129 



Genus 26. ftUADRULA P. E. Schulze, 1875. 



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



p. 458. 

 Quadrula F. E. Schulze in A.i'ch. mikr. Anat. XI, 2 (1875), 



p. .329. 



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

 a homogeneous chitinous 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 diifering 

 from those of Difflugia ; uninuclear. 



1. ftuadrula symmetrica (Wallich) P. E. Schulze. 

 (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 

 ■(188.5), p. 46.3, f. 1. 



Difflugia assulata Bheenbeeg in Abli. Akad. Wiss. Berlin, 

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



Difflugia carolinensis Ehrenbeeg in Abh. Akad. Wiss. 

 Berlin, 1871 (1872), pp. 246, 2-50, 274, t. iii, f. 14. 



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

 1871 (1872), pp. 2.54, 264, 274, t. iii, f. 15. 



Quadrula symmetrica P. B. Schdlze in Arch. mikr. Anat. 

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

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

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

 Aechee ill 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- 

 Reichs, I, 1 (1880), t. ii, f. 12 ; Lanessan in Rev. internat. 

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

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

 (1881), p. 106, t. iv, f. 1 ; Hitchcock Synops. Preshw. 

 Ilhiz. (1881), p. 19; Taeanek in- Sitzber. bohm. Ges. 



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