KONGL. «V. VET. AKADEMIENS HANDLINGAH. BAND 26. N:0 2. 89 



Forma minor Cl. — L. 0,03 to 0.045; B. 0,oir) to 0,023; at the eoustr. 0,013 to 0,o:i nun. 

 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. fnfilis A. S. Atl. XIII f. 17 from Zanzibar, but 

 the furrows are not drawn as dilated around the nodule. 



Var. mocsta A. S. 1881. — V. slightly constricted, li. 0,oy; B. 0,034; at the consti'. O.oay 

 mm. Transverse costse 7 in 0,01 mm. — Nav. moestd A. S. Atl. LXIX f. 18, 19. 



Marine, fossil: Baltjik (Atl.). 



7). homhoides is very nearly akin to D. splendidd, 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 PI. XXVII 

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



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

 to tongue-shaped segments. L. 0,o38 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 costte 11 in 

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

 Nav. divergcns A. S. Atl. XII f. 50, 51. 



Marine: Mediterranean Sea! 



Var. digrrdiens A. S. (1881). — V. less constricted. L. 0,04; B. 0,019; at the constr. 0,oit 

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

 Atl. LXIX, f. 26, 27. 



Marine: Tahiti! Baltjik, foss.! 



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

 shaped segments. L. 0,o27 to 0,075; B. O,oii to 0,o38; 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 costee 8 to 9 in 0,oi mm. crossed 

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

 Atl. XII f. 48; LXIX f. 23 (small, but typical). XIII f. 18, 19. — Icon. n. PI. I f. 20, 21. 



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



This form is nearly akin to D. dicergens. The fig. 18, 19 PI. XIII in A. S. Atl. greatly 

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

 LXIX f. 3G is probably also nearly related. 



40. D. chinensis 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. Costs 13 in 0,oi mm., alternating with single rows of 

 alveoli, about 16 in 0,oi mm. — PI. 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,o4; B. 0,02; at the constr. 0,oi mm. 

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

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

 middle of the valve. — Nav. Grundl. A. S. Zeitschr. f. ges. Naturw. 1873 p. 407 PI. 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 



