KONOL. SV. VET. AKADEMIENS IIANDLINOAH. BAND 26. N:0 2. 55 



b) Longitudinal lines double. 



Var. hicuneaid (tRUN. (18()()). — V. broad, lineai', with cuneate ends. L. (),ii to 0, ly; B. 

 0,0 18 to 0,032 mm. Striie \!) to 17 in (),oi nun. — Nav. bicimeafa (tRUN. Verh. 18(50 p. 546 PI. Ill 

 f. 4. A. S. N. S. D. PL II f. 44 (smaller form). N. maxima Donk. B. 1). p. OO PI. IX f. 4. 

 N. Bh'ischii A. S. Atl. L. f. 22, 23, 25. 



Marine: North Sea! Baltjik, fossil (Atl.), Sumatra (Deby Coll.!) Samoa (Atl.), Seychelles! 

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



Forma lanceolata. — V. shorter, with acuminate ends. L. 0,o8 to 0,09; B. 0,o32 mm. Striaj 

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



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



Var. excentrica Grun. (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. Striffi 20 to 22 in 0,oi mm. — Nav. excentrica GrRUN. 

 Verh. 1860 p. 545 PI. Ill f. I. N. delata A. S. N. S. D. p. 91 PI. 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 Coll.)! Japan (Atl.) Samoa! Colon 

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



B. Forms constricted in the middle. Central area ivithout lunate markings. 



Var. Janischiana Rabh. (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. Strite 

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



Marine: Colon (Deby Coll.)! 



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

 ends. L. 0,i4 to 0,17; B. 0,o2.'j (min.) to 0,042 (max.) in 0,oi mm. Areas indistinct. Striaj 12 in 

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

 f. 10. Cal. lil)cr var. Bleisch. Icon. n. PL IV f. 1. 



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

 (Grove Coll.)! 



C. Forms ivith lunate markings on the central area. 



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

 L. 0,07 to 0,12; B. 0,0 18 to 0,009 mm. Axial area narrow; central area small with lunate markings 

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

 - Na.v. elongata Grun. in A. S., N. S. D. p. 91 PL II f. 42. A. S. Atl. L. f. 27. 



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

 Florida! 



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

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

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

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

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



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



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

 B. 0,04 to 0,o:>.-) mm. Axial area narrow, but distinct, slightly dilated around the central nodule. 

 Striae 9 to 11 in 0,01 mm. Lcmgitudinal lines median, strong. — Nav. rolntsta Grun. in A. S. 

 Atl. L. f. 1-2. 



Marine: Zanzibar (Deby Coll.)! Java (Kinker f'oll.)! Sumatra! Singapore! Samoa! Redondo, 

 Calif, fossil (Gi'ove Coll.)! 



