10 D. ACUMINATA, Ehrenberg, Infus., 1838, 131, Taf. ix., fig. 3; 



Leidy, F. Rhiz. N. Amer., 109, pL xiii., figs. 1, 2, 8, 9, 11. 

 Plentiful near Cook's River, Waterloo Swamp, Parramatta 

 Park, and in Duck Creek, Clyde. Forms like figs. 14 and 

 20, in stone quarry, Moore Park ; rare. 



Arcella, Ehrenberg. 



11 A. vulgaris, Ehr, Abh. Akad Wiss. Berlin, 1830, p. 40, Taf. 



I., fig. 6 ; Leidy, 170, pi. xxvii., figs. 1, 2, 3, 11, 12, 25, 26, 

 27 and 28. Very abundant, almost everywhere, but a 

 very -^ariable species. The numbers of Leidy's figures given 

 above indicate forms similar to those I have observed from 

 different localities. I have seen forms like figs. 8, 9, 10, 

 and 1 1 on pi. xxviii. in Leidy's book, from Shea's Creek ; 



12 A. DiscoiDES, Ehr., Monatsb. Ak. Wiss., Berlin, 1848, 139; 



Leidy, F. Rhiz. N. Amer., 173, figs. 14, 15, 16, 17, 18, 

 23, 28, 30, 31. This is perhaps the most common of any ; 

 it is found associated with A. vulgaris and other species 

 in the greatest profusion. 



13 A. DENT ATA, Ehr., Abh. Akad. Wiss. Berlin, 1830, p. 40 ; 



Leidy, F. Rhiz. N. Amer., p. 177, pi. xxx., figs. 10-19. 

 This very beautiful species is rather rare. I have found 

 it only in two localities, in Shea's Creek and Cook's River. 

 In the latter place I found it on UtricuJaria; in the former 

 on the roots of grasses, sedges and fioating plants. Accord- 

 ing to Leidy's figures and description the number of spines 

 is from 9 to 12. The specimens observed by me had from 

 10 to 15, but their size and general characters are identical 

 with those of European and American examples. The 

 figures given in the " Micrographic Dictionary" and 

 also in Dr. Carpenter's "Microscope and its Revelations." 

 under the name of A. dentata, probably represent the var. 

 angulosa of A. vulr/aris. 



14 C. ACULEATA, Ehr., Abh. Akad. Wiss. Berlin, 1830, p. 40 ; 



Leidy, F. Riz. N. Amer.. 181, pi. xxxi., figs. 1, 3, 4, 12, 

 14, 23, 24, 27. A very common and variable species both 

 in the character of the materials by which the test is 



Waterloo Swamps, Cook's River, and many other places. 



CocuLioPODiUM, Hertwig and Lesser. 



15 C. BILIMB08A, Auerbach, Zeits. Wiss. Zoologie, vii.. 1856, 3/*, 



Taf. XIX., figs. 1-13 ; Lddv, F. Rhiz. N. Amer., 184, pi- 

 xxxii., figs. 1-25. Frequent on L>^mna and Au>na in Shea s 

 Creek, and on Utricnlaric near Cook's River. 



