KONGL. SV. VET. AKAUEMIKN8 HANDLINGAR. BAND 26. N:(J 2. 83 



Var. Eudoxiu A. S. (1875). — V. linear, with rounded eiids. L. 0,(i7 to 0,085; B. (),oi7 to 

 0,o-iL> mm. CcsttB (i to 7 in 0,oi mm. Fnrrows iiarrower, tlian oii the. type. — Nav. iitedifcrranea 

 A. S. N. S. I). Pl. II f. 10. Nac. Eudoxia A. S. Atl. VIII f. 40, LXX'f. 71. 



Marine: Morocco! Balearie Islands! Red Sea! Bab el mandeb! Madagascar! Ceylon! (7a]a- 

 pagus Islands! Monterey (Atl.). Fossil: Szåkal, Hungary! 



Var. Eugenia A. S. (1875). — V. with snbciineate ends. L. 0,o6; B. 0,oi7 mm. Costa' 7 

 to 8 in 0,0 1 mm. — Nav. Eugenia A. S. Atl. VIII f. 44. 



Marine: Ceylon (Leuduger Fortm.) Macassar Straits! Campeachy Bay (Atl.). 



There is, so far as I can see, no specilic distinction between the above forms, which I regard 

 as belonging to D. configua. They are perhaps all only smaller, and corroded, forms of D. gciinnatfr. 



15. D. circuiuiiodosa Brun. (1891). — V. very convex and thick, linear, witli broad, rounded 

 ends. L. 0,i; B. 0,02:3 mm. Central nodnle short and broad; its horns divergent at the nodule. 

 Fnrrows very broad. Costa^ 7 in 0, 01 mm., continued across the furrows as rows of three large 

 pnncta. — Nav. circumn. Brun. Esp. n. p. 00 Pl. XVI f. 2. 



Marine: Japan, fossil (Brnn CoU.)! 



16. 1). Letoiinieiiri Cl. N. Sp. — V. elongated, very .slightly constrieted in the middle, with 

 broad, rounded ends. L. 0,07," B. O.023; at the constr. 0,02. Central nodule elongated quadrate; its 

 horns nearly parallel. Furrows very broad. CostcE 9 in 0, 01 mm. almost parallel, continued 

 across the furrows, smooth. — Pl. I f. 18. 



Marine: Columbo, Ceylon (Letourneur CoU.)! 



17. D. imi.scieforniis Grun. (1875). — V. gently constrieted in the middle, with cuneate 

 ends. L. 0,07 to 0,09.5; B. 0,o3 to 0, 04 at the constr. 0, 024 to 0, 037 mm. Central nodule quadrate, 

 with approximate, scarcely divergent horns. Furrows V2 to '/^ as broad as the valve. CosttB 4 

 to 7 in 0,0 L mm., with faint contiuuations across the furrows. 



Var. plaeida A. S. L. 0,ou mm. Costa^ 4 to 4,5 in 0, 01 mm. — Nav. placida A. S. Atl. 

 CLXXIV f. 2. 



Marine: Galapagos Islands! San Pedro Calif. fossil (Kinker Coll.)! Oamaru New Zealand, 

 fossil (Atl.). 



Var. genuina Cl. — Costaj 7 in 0, 01 mm. — Nav. niuscwforni . A. S. Atl. XIII f. 42, 47. 



Marine: Campeachy Bay! Java! 



Var. constricta Gkun. — Ends rounded. L. 0,o5 to 0,o6; B. O.ois to O,oi'j at the constr. 

 0,0 13 to 0,0 15 mm. Costa? 6 to 7 in 0,01 mm. — Nav. constricta CtRUN.? A. S. Atl. XII f. 65; 

 LXIX f. 42. 



Marine: Balearie Islands! Sansego (Atl.), Seychelles (Van Heurck CoU.)! Madagascar! Sum- 

 bava (Kinker CoU.)! Japan (Beby CoU.)! Leton Bank (Atl.). 



Var. pusilla Cl. — V. slightly constrieted. L. 0,02; B. 0,oio mm. Costa', 9 in 0,oi mm. 



Marine: Galapagos Islands! 



This form is doubtful as. a species, having very much the appearance of strongly corroded 

 valves of other species as 1). Begrichiana and allied foi'ins. Grunow mention.s a form from tlie 

 Caspian Sea in length O, oas mm. and with 12 costa in 0, 01 mm., which seems not to belong to 

 D. inu.scceformis. 



18. D. constricta Grun. (1860). — V. gently constrieted in the middle, with subcuneate 

 ends. L. O.oe to 0,15; B. 0, 023 to 0,03, at the constr. 0,02 to 0,025 mm. Central nodnle quadrate, 

 its horns p^arallel, approximate. Furrows very broad. Costa 7 to 8 in 0,oi mm., very faint on 

 the furrows, radiate at the ends. — Nav. coH-strtctit. Grun. Verh. 1860 p. 535 Pl. III f. 18 (according 

 to V. H. T 103). Nav. Mu.vca Donk. B. D. p. 50 Pl. VII f. 6 (1873). Nav. Bonhinii A. S. N. S. 

 D. Pl. I f. 12 (1874); II f. 8. Atl. XII f. 63 64. 



Marine: Finmark! North Sea! Balearie Islands! Ce3d,oii! Florida! 



