KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 41 



Var. quadrata W. Sm. (1853). — V. rhomboidal, broad, slightly sigmoid. L. 0,i9; B. 0,048 mm. 

 Median line central. Central nodule small, elongated. Transv. and obi. striae '7i8 ™ 0,oi mm. — 

 P. angulatum W. Sm. Ann. M. Nat. H. [2] IX p. 7 Pi. I f . 7 (1852). P. qiiadr. W. Sm. B. D. I 

 p. 65 PL XX f. 204. Per. V f. 7, 8. P. ang. var. quadr. V. H. Syn. p. 115 Pi. XVIII f. 1. 



Marine: North Sea! 



Var. strigosa W. Sm. (1852). — Lanceolate, slightly sigmoid, gradually tapering to the sub- 

 acute ends. L. 0,i5 to 0,28; B. 0,o3 mm. Transv. and obi. strige equidistant, 18 to 22 in 0,oi mm. 

 Angle about 60°. — P. strigosum W. Sm. Ann. M. Nat. H. [2] IX p. 7 PI. I f. 6. B. D. I p. 64 

 PI. XXI £ 203; XXIII f. 203. Per. V f. 1, 2. P. ang. var. strig. V. H. Syn. p. 115 PI. XIX f. 2. 



Marine: North Sea! Mediterranean Sea! Adriatic! Red Sea! Ceylon! Java! South Africa! 

 Brazil! Florida! 



Var. finmarcMca Cl. (1884). — Gently sigmoid, more obtuse. Median line excentric towards 

 the ends. L. 0,i7 to 0,2; B. 0,03 mm. Transv. and obi. striae "/ui "Vu i^ ^'Oi mm. — P. Nor- 

 manii Cl. A. D. p. 14. Grun. A. D. p. 52 PL III f. 67. P. Finm. Grun. Franz Josephs Land 

 D. p. 105 (53). 



Marine: Finmark! 



Var.? convexum Geun. (1880). — V. very convex. L. 0,22.5; B. 0,02 mm. Median line some- 

 what excentric at the ends. Transv. and obi. striae ^"/jg in 0,oi mm. — P. strig. var.? convexa 

 Grun. a. D. p. 50. 



Marine: Puerto Caballo (Grun.). 



27. P. minutum Grun. (1878). — V. lanceolate, gently sigmoid. L. 0,o5 to 0,o65; B. 0,oi 1 

 to 0,0)4 mm. Median line nearly central. Transv. and obi. striae ^"^s' ^Vjs' "^^29 "^ *^''"' ™'^- 



— Grun. in Cl. M. D. 136. Icon. n. PL IV f. 19. P. eestuarii var. minuta Grun. A. D. p. 52. 

 Per. V f. 15. 



Brackish and marine: Sweden (Malmo! Lysekil, Grun.). Caspian Sea (Grun.), Balearic 

 Islands (Per.). 



This little form was placed by Grunow in the vicinity of P. eestuarii, with which it seems 

 to me not to have any close relation, as it differs by its non-rostrate ends, the nearly central me- 

 dian line, and the finer striation. It may perhaps be a dwarf-form of P. angulatum (strigosum). 



28. P. (Rhoicosigma) Stuxbergii Cl. and Grun. (1880). — V. narrow, lanceolate, gently 

 sigmoid, acute. L. 0,i9 to 0,38; B. 0,028 to 0,o32 mm. Median line central. Central nodule small, 

 rhomboid. Transv. and obi. striae 23/^^^ 24/^^^ 25^^^ [^ 0,oi mm. — A. D. p. 54 PL IV f. 74. Grun. 

 Franz Josephs Land D. p. 105 (53) PL I f. 56. Per. VI f. 9, 10. 



Marine: Franz Josephs Land (Grun.), Sea of Kara! Cape "Wankarema! 



Var. minor Grun. (1884). — L. 0,o8 to 0, 11; B. 0,oi6 to 0,oi7 mm. Transv. and obi. striae 

 ^Vsz in 0,01 mm. — Grun. Franz Josephs Land D. p. 105 PL I f. 57. Per. VI f. 11. 



Var. rhomboides Cl. (1880). — V. rhomboid-lanceolate, acute. L. 0,o85 to 0,13.5; B. 0,02 to 

 0,03 mm. Median line central, almost straight. Transv. and obi. striae ^i/^^^ 22/^4, ^72.5 in0,oi mm. 



— P. rhomb. Cl. A. D. p. 14, 54, PL IV f 73. Per. VI f. 14. 



Marine: Sea of Kara! Cape Wankarema! 



Var. latiuscula Per. (1891). — V. lanceolate, slightly sigmoid, with somewhat obtuse ends. 

 L. 0,16; B. 0,0 2 6 mm. Transv. and obi. striae 2720 in 0,oi mm. — P. latiusculum Per. p. 15 

 PL VI f. 12. 



Marine: North Sea (Per.). 



P. Stuxbergii, remarkable for its very fine oblique striae, is not related to P. delica- 

 tulum, but to P. acutum. The var. rhomboides seems to connect it with P. angulatum v. 

 strigosa. 



K. Vet. Akad. Handl. Band 26. N:o 2. 6 



