42 p. T. CLEVE, SYNOPSIS OF THE NAVICT'LOU) DIATOMS. • 



29. P. Briinii Cl. (1891). — V. linear, strongly sigmoid, suddenly attenuated to the acute 

 ends. Ij. 0,42 to 0,45; B. 0,3i to 0,03a mm. Median line central. Central nodiile small. Tj'aii.'!- 

 and oblique strife ''■''1^., in 0,oi mm. — Pek. p. K! 1*1. Vl f. 8. 



Marine (pelagic): Bay of Bengal! Java! 



30. P. javaniciim Giuin. (1878). — V. narrow, lanceolate, gently sigmoid, acute. L. 0,i2r) 

 to 0,144; B. 0,()i<,) to 0,022 mm. Median line nearly central in the middle, excentric towards the 

 ends. Transv. and old. strias e(piidistant, about 28 in 0,01 mm. — /'. (nninJatnni riir. jar. (tRUN. 

 in CI. M. I). 145. F. jaramcmn Grun. A. D. p. ^2 (18S()). Per. V f. 10. 



Marine (pelagic): Java! China! 



This species has the outline of P. afrigosnin, but is thinner (dry, yelloAvish) and more acute. 

 It is most nearly akin to P. acntuu). As P. liynVmnni, Grunow descril)es in A. I), (p. 52) a similar, 

 pelagic form from Triest (L. 0,08.'); B. (),(M().'> mm.), the striation of which is too delicate for measuring. 



31. P. aciitum Norm. (1861). - V. lanceolate, gently sigmoid, acute. L. 0,24 to 0,.!; B. 

 0,02 to 0,0 2 8 mm. Median line sigmoid, very excentric towards the ends. Transv. and obi. stria; 

 "/■iiJ -7i9> -''/io ill <-*.oi ii^in- — Norm. Pritch. Tnf. ]). 920. Per. Ill f. 1, 4. P. anitniu rar. unsfnil- 

 asicmn Grun" in Cl. M. D. 286 (1882). 



Marine (pelagic): Europe (Norm.), (!roisic (Per.), Java (Del)y Coll.)! St Vincent, Australia! 

 Yeddo Bay (Brun Coll.)! 



This .species is nearly akin to P. jdrairirmii and P. StHxhcrg'ii, from which latter it differs 

 by its less acute obli(iue stritc and the excentricity of its median line towards the ends. The Hg. 2 

 in Peragallo's monogi'aph has the outline and median line of P. Siuxhcrgii, but the striation (d' 

 P. (uatKui. The lig. 3 in the same monograjdi is another, allied form, described here as P. i)cla(iicHiii 

 Per. and formerlj' mistaken by me for ]\ ucufuni rar. (lusfrahisicttm Grix., whicli latter now seems 

 to me to be identical with P. acnfum. 



32. P. (Rlioicosignia?) niiiroceainim Cl. (1891). — V. narrow, lanceolate, gently .sigmoid, 

 gradually attenuated to the acute ends. L. 0,2 to 0,,t; B. 0,02 to (),i)a7 mm. Median line some- 

 what excentric, .sigmoid. Transv. and obi. sti'ia; '"/jg, ""'/19 in 0,oi mm. Angle about 70'. — Phoico- 

 sigtna marocc. Per. p. 32 PI. IX f. 22. 



Marine: Marocco! Gulf of Naples! 



This form is doubtful as a species and recpiires further examination. 



33. P. apstuarii Brii;b. (1849). — V. lanceolate, gently sigmoid, with slightly rostrate ends. 

 L. 0,07 to 0,08; B. 0,0 17 mm. Median line more sigmoid than the valve, excentric. Transv. and 

 obi. striae equidistant, 19 to 21 in 0,oi mm. — Naric. rest. Kutz. Sp. Alg. p. 890. P. cesf. W. Sm. 

 B. D. I p. 65 PI. XXXI f. 275. Grun. A. D. p. 52. Per. p. 12 Pi. V f. 11 to 13. P. camlidnw 

 ScHUM. Preuss. D. II Nachtr. PI. II f. 57 (1867). P. angidafum rar. test. V. H. Syn. p. 115 

 PI. XVIII f. 8. 



Marine: North Sea! Adriatic (Grun.), Caspian Sea (Cirun.), California! 



This species has the striation of P. fiiiguldtuni Imt, by the flexure of tiie median line, .seems 

 to be nearer akin to P. Janccolafum. 



34. P, latum Cl. (1880). — V. rhomboid-lanceolate, slightly sigmoid, gradually tapering to 

 the .siibobtuse ends. L. 0,o74 to 0,o8.5; B. 0,02111111. Median line slightly sigmoid, excentric towards 

 the ends. Transv. and obi. stria; '■^722 i" *''"' mm- — ^^- ^- D. p. 14, 51 PI. Ill f. 68. 



Marine: Finmark! California! 



This form requires a closer examination. 



35. P. rlionibeum Grun. (1880). — V. rhomboidal, sigmoid, often angular in the middle, 

 and with obtuse ends. L. 0,i2 to 0,2*;; B. 0,0;! to 0,07 mm. Median line strongly sigmoid towai'ds 



