K0N6L. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 55 



b) Longitudinal lines double. 



Var. hicuneata Geun. (1860). — V. broad, linear, with cuneate ends. L. 0,ii to 0,i9; B. 

 0,018 to 0,032 mm. Striae 15 to 17 in 0,oi mm. — Nav. hicuneata GtRUN. Verb. 1860 p. 546 PL III 

 f. 4. A. S. N. S. D. PL II f. 44 (smaller form). N. maxima Donk. B. D. p. 60 PL IX f. 4. 

 N. Bleischii A. S. Atl. L. f. 22, 23, 25. 



Marine: Nortb Sea! Baltjik, fossil (Atl.), Sumatra (Deby Coll.!) Samoa (Atl.), Seycbelles! 

 Colon (Deby Coll.)! Porto Seguro (Deby Coll.)! 



Forma lanceolata. — V. shorter, with acuminate ends. L. 0,08 to 0,o9; B. 0,o32 mm. Strise 

 about 13 in 0,oi mm. — Nav. excentrica A. S. Atl. L. f. 6, 7. 



Marine: Celebes (Atl.) Mazatlan (Atl.). 



Var. excentrica GrRUN. (1860). — V. broadly linear to linear-elliptical, with rounded or cuneate 

 ends. L. 0,o9 to 0,i4; B. 0,oi7 to 0,027 mm. Median line often slightly undulating. Central area 

 frequently slightly dilated unilaterally. Strise 20 to 22 in 0,oi mm. — Nav. excentrica Grun. 

 Verb. 1860 p. 545 PL III f. I. N delata A. S. N. S. D. p. 91 PL II f. 43 (1874). Atl. L. f. 30. 

 N. formosa v. fossilis Pant. II p. 45 PL XX f. 310 (1889). 



Marine: North Sea! Mediterranean Sea! Java (Kinker CoU.)! Japan (Atl.) Samoa! Colon 

 (Deby Coll.)! Hungary, fossil (Pant.). 



B. Forms constricted in the middle. Central area without lunate markings. 



Var. Janischiana Babh. (1862). — V. slightly constricted in the middle, with cuneate ends. 

 L. 0,14; B. 0,035 mm. Median line slightly flexuose. Central area small, asymmetrical. Strise 

 22 in 0,01 mm. Longitudinal lines faint, single. — Nav. Jan. Jan. Bab. Hond. p. 10 PL II f. 15. 



Marine: Colon (Deby Coll.)! 



Var. JBleischiana Jan. a. Rabh. (1862). — V. strongly constricted in the middle, with cuneate 

 ends. L. 0,i4 to 0,17; B. 0,025 (min.) to 0,042 (max.) in 0,oi mm. Areas indistinct. Strise 12 in 

 0,01 mm. Longitudinal lines single, very distinct. — Nav. Bl. Jan. a. Babh. Hond. p. 9 PL II 

 f. 10. Cal. liber var. Bleisch. Icon. n. PL IV f. 1. 



Marine: Honduras (Jan. Babh.) Nice (Deby, Brun, Van Heurck Coll.)! Redondo Calif, fossil 

 (Grove Coll.)! 



C. Forms with lunate markings on the central area. 



Var. elongata Grun. (1874). — Linear, with parallel margins and broad rounded ends. 

 L. 0,07 to 0,12; B. 0,018 to 0,009 mm. Axial area narrow; central area small with lunate markings 

 on both sides of the central nodule. Strise 15 to 18 in 0,oi mm. Longitudinal lines faint, median. 

 — Nav. elongata Grun. in A. S., N. S. D. p. 91 PL II f. 42. A. S. Atl. L. f. 27. 



Marine: North Sea! Mediterranean! Bed Sea! Ceylon! Singapore! Japan! Galapagos Islands ! 

 Florida! 



Var. umbilicata Grun. (1877). — V. linear, frequently slightly gibbous in the middle, with 

 rounded ends. L. 0,i3 to 0,i6; B. 0,015 to 0,02 mm. Axial area narrow, but distinct, somewhat 

 dilated in the middle, with linear markings on both sides of the central nodule. Strise 12 to 15 

 in 0,01 mm. Longitudinal lines distinct. — Nav. maxima var. umbilic. A. S. Atl. L. f. 32, 33. 

 Nav. max. v. asiatica Temp. Br. D. f. du Japon p. 72 (1889). 



Marine: North Sea (Atl.) Bab el mandeb! Ceylon! Japan, fossil (Brun.) Colon (Deby Coll.!). 



19. C. robusta Grun. (1877). — V. linear, narrowed towards the ends. L. 0,28 to 0,33; 

 B. 0,0 4 to 0,0 3 5 mm. Axial area narrow, but distinct, slightly dilated around the central nodule. 

 Strise 9 to 11 in 0,oi mm. Longitudinal lines median, strong. — Nav. robusta Grun. in A. S. 

 Atl. L. f. 1-2. 



Marine: Zanzibar (Deby Coll.)! Java (Kinker Coll.)! Sumatra! Singapore! Samoa! Bedondo, 

 Calif, fossil (Grove Coll.)! 



