KONGL. SV. A^ET. AKADKMIENS HANDLINGAR. BAND 26. N:0 2. 



( "V. very convex P. crncifix Bb. a. Temp. 



\ V. less convex 4. 



I Stri;e poarsely ])uni't,ate P. jnytita Cl. 



^ — finely — P- sfnurnjjtera BAir,. 



71 



1. P. iii)i)leta Cl. a. G-rove (1891). — V. elliptic-lanceolate. L. 0,13; B. 0,o.-i8 mm. Median 

 line with very approximate central pores and indistinct terminal flssiires. Stanros narrow dilated 

 at the extremities. Strise 12 in O, di mm., radiate thvong-hont, finely lineate. Longitudinal lines 3 

 to 4 on each lialf of the valve, tlie most distinct conneeting tlie ends of the staiiros with the ends 

 of the valve. — Nav. impl. Cl. a. G-ROVE. Diatoniiste I, p. .58 Pl. IX fig. 1. 



Marine: Macassar Straits! 



2. P. polygoiia Brun (1891). — V. broad with .slightly convex margins and euneate, ohtnse, 

 ends. L. 0, 12 to 0,iä; B. 0,0 3 5 to 0,0 5 mm. Median line with small terminal fissnres, tnnied in 

 the same direction, and not very approximate central pores. Stanros moderately broad. Strise 

 slightly radiate thronghont, 16 in 0,oi mm., pnnctate, puncta 21 in 0,ni mm. Longitndinal lines 

 not very distinct. — Nav. pol. Brun. D. Esp. n. p. 38 Pl. XV f. 9. 



Marine: Japan, fossil! 



The longitndinal lines are not so distinct as on the 

 other species. In tlieir place is a kind af low crest sepa- 

 rating the interiör part of tlie valve fi'om the exteriör 

 steeply sloping part. 



3. P. staiiroptera Bail. (1854). — V. elliptic-lanceo- 

 late, vrith obtnse ends. L, 0, 11 to 0,13; B. 0, 03 to f>,035 

 mm. Stauros moderately broad. StricC. 14 to 18 in 0,oi 

 mm., finely pnnctate, parallel. Longitndinal lines distinct, 

 median. — Ampliora staiiroptera Bail. Smiths. Contr. VII 

 p. 8 f. 14, 15 (1854). AmpMprora lepidoptera G-rbg. D. of 

 Clyde p. 506 Pl. XII f. 59 c (1857). Ampldprora obsusa 

 Greg. D. of Clyde 1. c. % 60. A. S. N. S. D. III f. 1. 

 Nav. arctica Cl. D. aret. S. p. 16 Pl. III f. 13 (1873). 

 Lagerst. Boh. D. p. 46. Cl. N. II. D. p. 13. 



Marine: Sea of Kära (Grnn.). Finmark! North Sea! 

 Nova Scotia (Bail). Sidney (Brun CoU.!). 



4. P. jugata Cl. (1881). — V. lanceolate, with ob- 

 tnse ends. L. 0,o68 to 0,093; B. 0,02 to 0, 024 mm. Stanros 

 of median breadth. Strite 10 in 0,oi mm. parallel, more distinct ontside the longitndinal lines, 

 distinctly pnnctate; puncta aboiit 12 in 0,oi mm. Longitndinal lines median. — Nav. jugata Cl. 

 N. R. D. p. 13 Pl. III f. 38. 



Marine: Galapagos Islands! 



Var. Fensaeolce Cl. (1881). — V. slightly trinndnlate, with subrostrate ends. L. 0,054; B. 

 0,0 15. StrifE 15 in 0,oi mm. — Nav. Pensacola Cl. N. R. D. p. 14 Pl. III f. 39. 

 Marine: Pensacola! 



P. staiiroptera 500 timei5 magiiified. 



5. P. crncifix Temp. a. Brun. (1889). — V. very convex, narrow, lanceolate, with .siTbacute 

 ends. L. 0,12; B. 0,022 mm. Stanros moderately bi^oad. Strite 16 in 0,oi mm. parallel, pnnctate; 

 puncta about 16 in 0, 01 mm. Longitudinal lines marginal. — Nar. criic. D. foss. du Japon p. 42 

 Pl. VII f. 10. 



Marine: Japan, fossil! 



