K0N6L. SV. VET. AKADEMIENS HANDLINGAB. BAND 26. N:0 2. 89 



Forma minor Cl. — L. 0,03 to 0,045; B. 0,oi5 to 0,023; at the constr. 0,oi3 to 0,02 mm. 

 Central nodule small. Transverse costse 11 in 0,oi mm.; longitudinal 9 in 0,oi mm. 



Marine: Tahiti! Madagascar! 



The f. minor may be the same as Nav. futilis A. S. Atl. XIII f. 17 from Zanzibar, but 

 the furrows are not drawn as dilated around the nodule. 



Var. moesta A. S. 1881. — V. slightly constricted. L. 0,09; B. 0,o3+; at the constr. 0,029 

 mm. Transverse costse 7 in 0,oi mm. — Nav. moesta A. S. Atl. LXIX f. 18, 19. 



Marine, fossil: Baltjik (Atl.). 



D. homhoides is very nearly akin to D. splendida, from which it differs only in the furrows 

 which are slightly dilated around the nodule, a characteristic which seems to be variable. To judge 

 from specimens from Bory Deposit in Hungary Nav. andesitica Pant. (1889, II p. 42 PL XXVII 

 f. 390) seems to be somewhat corroded specimens of D. bomboides with rather closer costse. 



38. D. diyergens A. S. (1875). — V. more or less constricted in the middle, with elliptical 

 to tongue-shaped segments. L. 0,038 to 0,045; B. 0,oi8 to 0,02; at the constr. 0,oi2 to 0,oi3 mm. 

 Central nodule small, quadrate; its horns divergent at the basis, convergent at the ends. Furrows 

 linear, broader around the central nodule, forming a lanceolate space. Transverse costse 11 in 

 0,01 mm., crossed on each side of the median line by about 5 longitudinal, slightly curved costse. — 

 Nav. divergens A. S. Atl. XII f. 50,' 51. 



Marine: Mediterranean Sea! 



Var. digrediens A. S. (1881). — V. less constricted. L. 0,04; B. 0,oi9; at the constr. 0,oi7 

 mm. Transverse costse 13 in 0,oi mm. Longitudinal costse less distinct. — Nav. digrediens A. S. 

 Atl. LXIX, f. 26, 27. 



Marine: Tahiti! Baltjik, foss.! 



39. D. Hchmidtii Cl. N. Sp. — V. slightly constricted in the middle, with broad tongue- 

 shaped segments. L. 0,027 to 0,075; B. 0,oii to 0,038; at the constr. 0,oio5 to 0,027 mm. Central 

 nodule small, quadrate; its horns divergent in the middle. Furrows broader in the middle, 

 narrower at the ends, with faint traces of the costse. Transverse costse 8 to 9 in 0,oi mm. crossed 

 on each side of the median line by 3 to 4 more or less undulating longitudinal costse. — A. S. 

 Atl. XII f. 48; LXIX f. 23 (smaU, but typical). XHI f. 18, 19. — Icon. n. PL I f. 20, 21. 



Marine: Seychelles! Madagascar! Port Jackson! Tahiti! Galapagos Islands! 



This form is nearly akin to Z). divergens. The fig. 18, 19 PL XIII in A. S. Atl. greatly 

 resembles larger specimens of D. Schmidtii, but has not divergent horns. Nav. vana A. S. Atl. 

 LXIX f. 30 is probably also nearly related. 



40. D. chlnensis Cl. N. Sp. — V. slightly constricted, with broad, rounded ends. L. O.055; 

 B. 0,02; at the constr. 0,oi3 mm. Central nodule elongated, quadrate; its horns parallel. Furrows 

 narrow, linear, not dilated in the middle. Costse 13 in 0,oi mm., alternating with single rows of 

 alveoli, about 16 in 0,oi mm. — PL I f. 25. 



Marine: China (Thum). 



41. D. Grundleri A. S. (1873). — V. deeply constricted, very convex. Segments semi- 

 orbicular to broadly tongue-shaped, often of inequal size. L. 0,04; B. 0,02; at the constr. 0,oi mm. 

 Central nodule quadrate, large, with divergent horns. Furrows narrow, broader in the middle. 

 Transverse costse 7 in 0,01 mm., crossed by 2 to 4 longitudinal costse, usually interrupted in the 

 middle of the valve. — Nav. Grundl. A. S. Zeitschr. f. ges. Naturw. 1873 p. 407 PL VI f. 5, 6. 

 Atl. XII f. 35, 36. 



Marine: Balearic Islands! Bab-el-Mandeb! Philppines! Atlantic coast of N. America! Para 



River (A. S.). 



K. Vet. Akad. Handl. Band 26. N:o 2. 12 



