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 

 bent around the large central nodule. Costse 7 in 0,oi mm. — Nav. hyperborea GtRUN. Verb. 1860 

 p. 531 PI. Ill f. 16. Nav. propinqm A. S. Atl. VII f. 13? 



Marine: Bohuslan, Sweden (Grrun.). 



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

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

 Marine: North Sea (Atl.). 



60. D. vacillans A. S. (1875). — V. elongated elliptical,' constricted, or not constricted. 

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

 the valve a lanceolate space. Costse 9 to 14, alveoli 15 to 21 in 0,oi 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 £ 61; XII f. 42, 

 43, 52, 53. 



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

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



Forma /?. V. not constricted in the middle. — A. S. Atl. VIII f. 34, 35, 36. — Nav. parca 

 var. producta 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. Striae 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. 0,05; B. 0,oi8 mm. Costse 10 in 

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



Marine: Celebes (Atl.). 



Var. corsicana Grtjn. (1878). — V. slightly constricted. L. 0,065; B. 0,022 mm. Costse 8, 

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



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



Var.? minuta Geun. (1880). — V. slightly constricted. L. 0,oi4 to 0,02; B. 0,oo45 mm. 

 Costse about 16 in 0,oi mm.. — Nav. vacillans f. minuta (N. Ffitzeriana 0. W.) V. H. Syn. 

 p. 90 PI. IX f. 9. 



Marine: Belgium (V. H.). 



61. D. Parma Cl. (1891). — V. broadly elliptical. L. 0,o3; B. 0,02 mm. Central nodule 

 moderately large, rounded quadrate. Furrows arcuate, equally bent, approximate to the horns. 

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

 p. 43 PL II f. 10. 



Fresh water: Sweden, Lake Rosslangen i Kalmar Lan! Finland, Abo, Viando! 

 Similar to D. finniea but only half the size and with costse and alveoli twice as close. 



62. D. flnuica Ehb. (1838) Ol. — V. broadly elliptical. L. 0,o5 to 0,055; B. 0,o34 to 0,036 

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

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

 mm. forming longitudinal or near the margin obliquely decussating rows. — Goccon. finniea Ehb. 

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



Fresh water: Sweden, Lake Roslangen! Degernas in Westerbotten, fossil! Finland! U. States 

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



63. D. microtatos 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. Furrows broad; their outer margins enclosing an eUiptical 



