KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 95 



59. D. hyperborea Grun. (1860). — V. elliptical. L. 0,i; B. 0,o49 mm. Furrows abruptly 

 beut arouncl the large central nodx;le. Costse 7 in 0,oi mm. — Nav. hyperhorea (iRun. Verli. 1860 

 p. 531 Pl. III f. 16. Nav. propinqua A. S. Atl. VII f. 13? 



Marine: Bohuslän, Sweclen ((xrnn.). 



Var. excisa A. S. (1874). — V. sliglitly constricted in the middle. L. 0,09; B. 0,o3 mm. 

 Costae 9 in 0,oi nim. — Nav. fusca var. excisa A. S. N. S. D. II f. 9. 

 Marine: North Sea (Atl.). 



60. D. vacillans A. S. (187.5). — V. elongated elliptical,' constricted, or not constricted. 

 L. 0,04 to 0,06; B. 0,oi4 to 0,oi6 mm. Furz-ows dilated in the middle, forming in the middle ot 

 the valve a lanceolate space. Costee 9 to 14, alveoli 15 to 21 in 0, 01 mm. Alveoli forming longi- 

 tudinal rows parallel with the margins of the areas. 



Forma a. V. constricted in the middle. — Nav. vacillans A. S. Atl. VIII f. 61; XII f. 42, 

 43, 52, 53. 



Marine: Ceylon (Leuduger Fortm.) Rodriguez! Cape Good Hope (Atl.), Japan (Atl.), Samoa 

 (Atl.), Sandwich Island (Atl.), Cape Horn (Petit), Campeachy Bank (Atl.), California (Atl.). 



Forma fi. V. not constricted in the middle. — A. S. Atl. VIII f. 34, 35, 36. ~ Nav. imrca 

 var. prodiida Pant. II p. 52 Pl. VIII f. 148 (1889). 



Marine: North Sea (Atl.), Marocco! Balearic Islands! Macassar Straits! Colon (Deby Coll.)! 

 Campeachy Bay (Atl.). 



Var. delicatula Cl. — not constricted. Strije 13 to 14 in 0,oi mm. — A. S. Atl VIII f. 37. 



Marine: Cape Good Hope (Atl.). 



Var. renitens A. S. (1875). — V. strongly constricted. L. 0,0 5; B. 0,oi8 mm. Costee 10 in 

 0,01 mm. — Nav. vacill. v. renitens A. S. Atl. XII f. 55. 



Marine: Celebes (Atl.). 



Var. corsicana Grdn. (1878). — V. slightly constricted. L. 0,065 ; B. 0,u2 2 mm. Costte 8, 

 alveoli 18 in 0,oi mm. — Cl. M. D. N:o 153. 



Marine: Corsica! Seychelles (Van Heiirck Coll.)! Campeachy Bay! 



Var.? minuta Grdn. (1880). — V. slightly constricted. L. 0,oi4 to 0,02; B. 0,oo4 5 mm. 

 CostiB abont 16 in 0, 01 mm.. — Nav. vacillans f. minuta {N. Ffitzeriana O. W.) V. H. Syn. 

 p. 90 Pl. IX f. 9. 



Marine: Belgium (V. H.). 



61. D. Pariua Cl. (1891). — V. broadly elliptical. L. 0,0.3; B. 0,02 mm. Central nodule 

 moderately large, rounded qnadrate. Furrows arcuate, eqnally bent, approximate to the horns. 

 CostcE 14 in 0,01 mm. Alveoli 20 in 0, 01 mm., forming longitudinal rows. — Cl. D. of Finland 

 p. 43 Pl. II f. 10. 



Fresh water: Sweden, Lake Rosslängen i Kalmar Län! Finland, Åbo, Viando! 

 Similar to Z>. finnica but only half the size and with costpe and alveoli twice as close. 



62. D. finnica Ehb. (1838) Cl. — V. broadly elliptical. L. 0,05 to 0,o5r,; B. 0,o34 to 0,o36 

 mm. Central nodule small, elongated. Furrows broad, with arcuate exteriör margins enclosing 

 a large, lanceolate space, abont one third of the valve. Costse 7 in 0, 01 mm. Alveoli 12 in 0,oi 

 mm. forming longitudinal or near the margin obliquely decussating rows. ' — Coccon. finnica Ehb. 

 Inf. p. 194. M. G. XVII, 2 f. 19. D. finnica Cl. D. of Finland p. 43 Pl. II f. 11. 



Fresh water: Sweden, Lake Roslängen! Degernäs in Westerbotten, fossil! Finland! U. States 

 Albany, Maine, fossil! Crane Pond, fossil! Canada, fossil! 



63. D. mierotatos Pant. (1886). — V. orbicular. L. and B. 0,034 to 0,04 mm. Central 

 nodule large, not .sharply defined. Median line with distant central pores, and ending at a consi- 

 derable distance from the margin. Furro^srs broad; their outer margins enclosing an elliptical 



