KONGL. SV. VET. AKADEMIENS HANDLINGAR. BANT) 



26. 



n:o 



71 



{V. very convex . . . 

 V. less convex . . . 

 I Striae coarsely punctate 

 \ ^ finely — 



P. crucifix Bk. a. Temp. 

 . ... 4. 

 . . P. jugata Cl. 

 . P. stauroptera Bail. 



1. P. impleta Cl. a. Grove (1891). — V. elliptic-lanceolate. L. 0,i3; B. 0,038 mm. Median 

 line with very approximate central pores and indistinct terminal fissures. Stauros narrow dilated 

 at the extremities. Strise 12 in 0,oi mm., radiate throughout, finely lineate. Longitudinal lines 3 

 to 4 on each half of the valve, the most distinct connecting the ends of the stauros with the ends 

 of the valve. — Nav. impl. Cl. a. GtROVB. Diatomiste I, p. 58 PL IX fig. 1. 



Marine: Macassar Straits! 



2. P. polygona Brun (1891). — V. broad with slightly convex margins and cuneate, obtuse, 

 ends. L. 0,i2 to 0,i5; B. 0,035 to 0,05 mm. Median line with small terminal fissures, turned in 

 the same direction, and not very approximate central pores. Stauros moderately broad. Striae 

 slightly radiate throughout, 16 in 0,oi mm., punctate, puncta 21 in 0,oi mm. Longitudinal lines 

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



Marine: Japan, fossil! 



The longitudinal lines are not so distinct as on the 

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

 rating the interior part of the valve from the exterior 

 steeply sloping part. 



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

 late, with obtuse ends. L, 0,ii to 0,i3; B. 0,o3 to 0,o35 

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

 mm., finely punctate, parallel. Longitudinal lines distinct, 

 median. — Amphora stauroptera Bail. Smiths. Contr. VII 

 p. 8 f. 14, 15 (1854). Amphiprora lepidoptera GtReg. D. of 

 Clyde p. 506 PL XII f. 59 c (1857). Amphiprora ohsusa 

 Greg. D. of Clyde 1. c. fig. 60. A. S. N. S. D. Ill f. 1. 

 Nav. arctica Cl. D. arct. S. p. 16 PL III f. 13 (1873). 

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



Marine: Sea of Kara (Grun.). Finmark! North Sea! 

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



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

 tuse ends. L. 0,068 to 0,093; B. 0,o2 to 0,024 mm. Stauros 

 of median breadth. Striae 10 in 0,oi mm. parallel, more distinct outside the longitudinal lines, 

 distinctly punctate; puncta about 12 in 0,oi mm. Longitudinal lines median. — Nav. jugata Cl. 

 N. E. D. p. 13 PL III f. 38. 



Marine: Galapagos Islands! 



Var. Pensacolce Cl. (1881). — V. slightly triundulate, with subrostrate ends. L. 0,0.54; B. 

 0,015. Striae 15 in 0,oi mm. — Nav. Pensacolce Cl. N. R. D. p. 14 PL III f. 39. 

 Marine: Pensacola! 



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

 ends. L. 0,12; B. 0,022 mm. Stauros moderately broad. Striae 16 in 0,oi mm. parallel, punctate; 

 puncta about 16 in 0,oi mm. Longitudinal lines marginal. — Nav. cruc. D. foss. du Japon p. 42 

 PL VII f. 10. 



Marine: Japan, fossil! 



P. stauroptera 500 times magnified. 



