KONOL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 87 



32. D. bombiformis Cl. N. Sp. — V. deeply constricted in the middle, with broad seg- 

 ments. L. 0,032; B. 0,014 mm. Central nodule small, its horns strongly divergent. Furrows nar- 

 row. Costse 8 in 0,oi mm. crossed by a longitudinal line. — PI. I f. 26. 



Marine: Macassar Straits (Grrove Coll.)! 



This form may be a small variety of D. Bomhus. 



33. D. Clepsydra Cl. N. Sp. — V. strongly constricted, with almost orbicular segments. 

 L. 0,07; B. 0,032; at the constr. 0,oi6 mm. Central nodule large, quadrate; its horns divergent in 

 the middle. Furrows narrowed in the middle and at the ends, crossed by faint costse. Costse 7 

 in 0,01 mm. strongly radiate, alternating with single rows of alveoli. — PI. I f. 29. 



Marine: Madagascar! 



34. D. Praestes A. S. (1875). — V. elongated, slightly constricted, with narrow elliptical 

 segments. L. 0,o7 to 0,12; B. 0,oi9 to 0,025; at the constriction 0,o is to 0,oi7 mm. Central nodule 

 small, quadrate; its horns parallel. Furrows linear, moderately narrow. Costse almost parallel, 

 fi to 7 in 0,01 mm., alternating with rows of indistinct puncta. — Nav. Preestes A. S. Atl. XII 

 f. 57, 58. 



Marine: Gulf of Naples (Thum.)! Alexandria (Deby Coll.)! Red Sea (Deby Coll.)! Mazatlan 

 (Atl.). Campeachy Bay (Atl.). 



D. Frcestes is nearly allied to D: Guinardiann, from which it differs by somewhat coarser 

 costae and the rows of alveoli alternating with the costse. It seems to be very probable that 

 D. Guinardiana is only a corroded D. Preestes. 



35. D. Entomon (Ehb. 1844) A. S. — V. elongated, slightly constricted in the middle, with 

 tongue-shaped segments. L. 0,o72 to 0,i5; B. 0,028 to 0,042; at the constr. 0,026 to 0,3.5 mm. 

 Central nodule large, quadrate, its horns parallel. Furrows moderately wide, linear, forming a space 

 of about a third of the width of the valve, often dilated around the central nodule. Costse 6 to 8 

 in 0,01 mm. parallel, at the ends divergent, anastomosing with a few (1 to 4) longitudinal, irregularly 

 undulating, more or less distinct, costse. • — Dipl. Entomon Ehb. Berl. Ber. 1844 accord to Chase. 

 Nav. Entomon A. S. N. S. D. PL 1 f. 13, 14; Atl. XIII f. 48, 49. Nav. homboides var. media Grun. 

 A. D. p. 41 PI. Ill f. 54. Nav. homboides A. S. Atl. XIII f. 38. 



Marine: Arctic America! Spitsbergen! Kara! Finmark! North Sea! Mediterranean Sea! 

 Adria! Samoa! Sidney! China! Japan! Behrings Island! Mexillones, Peru (Deby Coll.)! Fossil: 

 Brunn, Tegel! Bory, Hungary! 



D. Entomon is not a sharply defined species, graduating as it seems into D. splendida, with 

 which many of its varieties are closely connected. 



36. D. splendida Greg. (1856). — V. elongated, panduriform. L. 0,055 to 0,22; B. 0,02 to 

 0,05; at the constr. 0,oi5 to 0,03 mm. Central nodule large, quadrate; its horns parallel. Furrows 

 narrow, linear, not dilated around the central nodule. Transverse costse 5 to 8 in 0, 01 mm.; crossed 

 on each side of the median line by 4 to 6, slightly curved or undulating longitudinal costse. — 

 Nav. splendida GreCx. T. M. S. IV p. 44 PI. V f. 14. V. H. S. PL IX f. 4. A. S. N. S. D. 

 PL I f. 3, 4, PL II f. 2. Atl. XIII f. 31, 32, 34. Nar. Entomon Donk. B. D. p. 49 PL VII f. 5. 

 Nav. didyma var. Greg. T. M. S. IV p. 45 PL V f. 16. Nav. gemmatula Cl. Quek. M. CL II (2) 

 p. 167 pi. XII f. 1 (1885). Na.v. Taschenbergeri A. S. Atl. CLXXIV f. 9; 1892 (a large and coarse 

 form). N. margaritifera Pant. Ill PL XXXV f. 494 (1893)? 



Marine: Greenland! Spitsbergen! Beer en Eiland! Finmark! North Sea! Ceylon! Madagascar! 

 Java! Sumatra! Port Jackson! Japan! Sandwich Islands (Atl.). West Indies! Florida! Fossil: 

 Moravian Tegel! S:a Monica, Calif.! 



