KONGL. SV. VET. AKADEMIENS IlANDl.lNGAH. BAND 26. N:0 2. 101 



nating with double rows of somewhat coarse puneta (8 to 11 in (),oi mm.). — Nav. expleta A. S. 

 Atl. l.XIX f. 7, 8. 



Marine: Zanzibar! Celebes (Atl.), Society Islands! 



This form differs from var. Pandura by its shorter, less constricted valves. 



Var. Didclta Cl. — V. slightly constricted, with almost triangular segments. L. 0,o8 5; 

 B. 0,04; at the constriction 0,o28 mm. Costi^ 8 in 0,oi mm. — PI. II f. 8. 



Marine: Sumbava (Kinker Coll.)! 



Var. siihelliptica Cl. — V. elongated, not at all, or very slightly, constricted. L. 0,i5; 

 B. 0,052. CostiK 3 to 4 in 0,oi mm. alternating with double rows of coarse puneta, about 8 in 0,oi 

 mm. — PI. II f. 11. 



Marine: vSouth America, fossil! Macassar Straits (corroded form with 4 to 5 costee in 0,oi 

 mm. in Grove Coll.)! Galapagos Islaixls (perfectly elliptical form. L. 0,o8; B. 0,04 mm. CostiT-, 5 

 in 0,0 1 mm. Ocelli not distinct). 



Var.? Fandurella Cl. — V. strongly constricted with subelliptical segments. L. 0,03 8 to 

 0,075; B. 0,011 to 0,022; at the constriction 0,007 to 0,oi3 mm. Costte 8 to 9 in 0,oi mm. alter- 

 nating with double rows of puneta, about 20 in (),oi mm. Rows of ocelli indistinct. — PI. II f. 9. 



Marine: Indian Ocean (Deby Coll.)! China! Galapagos Islands! 



This form resembles in all respects the var. Pandura, but is much smaller and has closer 

 costse. As I have not seen any rows of ocelli I am doubtful whether this form is to be regarded 

 as belonging to this group; nevertheless it is related to the var. Pandura as the var. suspecta to 

 the var. .separahilis and the var. Dirhombus to the var. muUicostata. 



B. Forms tvith moderately vide lunulce. 



Var. separahilis A. S. (1875). — V. gently constricted with elliptical segments. L. 0,08 to 

 0,16; B. 0,0.33 to 0,05; at the constriction 0,026 to 0,032 mm. Costee 5 to 6 in 0,oi mm. Lunula 

 narrow. — Nav. Crabro Grev. M. J. V. p. 7 PI. Ill f. 11. JSfav. Grevillei Donk. B. D. p. 47. 

 Nav. separahilis A. S. Atl. XI f. 3, 5, 6, 7, 10, 17. — N. Crabro var. Joponica A. S. Atl. 

 CLXXIV f. 4? 



Marine: Pelew Island (Atl.), Singapore (Deby Coll.)! Puerto Caballo (Atl.), Campeachy Bay 

 (Atl.), Trinidad (Grev.). 



This form is intermediate between var. Pandura and var. multicostata. 



Var. hungarica Cl. — V. elliptical, not constricted. L. 0,o6; B. 0,o3 mm. Row of ocelli 

 marginal, not bent toward the central nodule. Costse 5 in 0,oi mm. Lunulse narrow. — PI. II f. 10. 



Marine: Szakal (Hungary, fossil)! Galapagos Islands! 



Var. f/loriosa Brun (1891). — V. slightly constricted, vith tongue-shaped segments. L. 0, 11 

 to 0,2; B. 0,04 to 0,074: at the constriction 0,o25 to 0,o6 mm. Central nodule large. Lunula; 

 narrow. Costse 3 to 3,5 in 0,oi mm. alternating with double rows of large puneta, about 8 inO,oi 

 mm. Ocelli usually indistinct. — Nav. yloriosa Brun D. esp. n. p. 34 PL XV f. 8. 



Marine: Mexillones Bolivia! Hakodadi, Japan (Deby Coll.)! 



This is the stoutest and most beautiful of all the forms of D. Crabro. The outline varies. 

 Some specimens are deeply and abruptly constricted, others scarcely constricted. The ocelli are 

 usually not distinct, but in some specimens easily seen. The breadth of the lunula?, is also variable. 



Var.? susjH'cta A. S. (1875). — V. strongly constricted, with elliptical segments. L. 0,o4 6 

 to 0,092; B. 0,012 to 0,03; at the constriction 0,oo6 to O.on-, mm. Costce 5 in 0,oi mm. Ocelli 

 not distinct. — Nav. suspecta A. S. Atl. XI f. 12, 13, 26, 27. Nav. yloriosa var. inflata Brun D. 

 esp. n. p. 34 PI. XV f. 12. 



Marine: Manilla (Deby Coll.)! Singapore (Van Heurck Coll.)! Java! Japan (Atl.), Galapagos 

 Islands! Mexillones, Bolivia (Brun Coll.)! Campeachy Bay (Atl.). 



I have placed this form among the varieties of D. Crabro, only with hesitation, as I never 

 observed on it the marginal row of ocelli, by which the other forms are characterized. 



