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



b) Longitudinal lines doitble. 



Var. hinmeata GtRUN. (1860). — V. broad, linear, witli cuneate ends. L. 0,n to 0, 19; B. 

 0,018 to 0,o3i> mm. Strise 15 to 17 in 0,oi mm. — Nav. bictmeata Grun. Verh. 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: North Sea! Baltjik, fossil (Atl.), Sumatra (Deby Coll.!) Samoa (Atl.), Seychelles! 

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



Forma lanceoJata. — V. sliorter, with acuraiiiate ends. L. 0,o8 to 0, 09; B. 0, 03 2 mm. Striee 

 about 13 in 0, 01 mm. — Nav. excentrica A. S. Atl. L. f. 6, 7. 



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



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

 ends. L. O, o 9 to 0,14; B. 0,oi7 to 0,027 mm. Median line often slightly undulating. Central area 

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

 Verh. 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 Coll.)! Japan (Atl.) Samoa! Colon 

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



B. Forms constricied in tlie middle. Central area ivithout lunafe markings. 



Var. Janincliiana Rabh. (1862). — V. slightly constricied in the middle, with ciineate ends. 

 L. 0,14; B. 0,03 5 mm. Median line slightly flexuose. Central area small, asymmetrical. StriiE 

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

 ends. L. 0, 14 to 0,17; B. 0,o2,t (min.) to 0, 042 (max.) in 0, 01 mm. Areas indistinct. Striaä 12 in 

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

 f. 10. Gal. liber var. Bleisch. Icon. n. Pl. IV f. 1. 



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

 (Grove Coll.)! 



C. Forms ivitli lunate marhings on the central area. 



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

 L. 0,0 7 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 nodule. Striee 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! Red Sea! Ceylon! Singapore! Japan! Galapagos Islands! 

 Florida! 



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

 rounded ends. L. 0, 13 to O, le; B. 0, 01. t to 0,02 mm. Axial area narrow, but distinct, somewhat 

 dilated in the middle, with linear markings on both sides of the central nodule. Strite 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. 0,04 to 0,1)3.-) mm. Axial area narrow, but distinct. slightly dilated aro^xnd the central nodule. 

 Strise 9 to 11 in 0, 01 mm. Longitudinal lines median, strong. — Nav. robusta Grun. in A. S. 

 Atl. L. f. 1-2. 



Marine: Zanzibar (Deby Coll.)! Java (Kinker Coll.)! Sumati-a! Singapore! Samoa! Redondo, 

 Calif. fossil (Grove Coll.)! 



