40 r. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



23. P. Oriiiulleri Grun. (1880). — V. lanceolate, gently sigmoid, gradually tapering to the 

 subacute ends. L. 0,.36 to 0,46; B. 0,o62 to 0,072 mm. Median line slightly sigmoid, central. Transv. 

 and obi. striiB '^',, in 0,oi mm. — GrRUN. A. I), p. 54. Per. p. 15 PL VI f. I. 



Marine: Campeachy Bay (Grrun.). 



This species is according to Peragallo nothing but a variety of P. rigUJam. It seems me 

 to be more nearly related to P. strigosum. 



24. P. australe Grun. (1867). — V. linear, lanceolate, sigmoid, with obtuse ends. L. 0,o8 

 to 0,11; B. 0,0 17 mm. Median line central, sigmoid. Central nodule large, rounded. Median stria? 

 more distant than the terminal. Transv. stria' 21 to 23 in (),oi mm.; obi. strife 18 to 20 in the 

 middle and 20 to 23 in 0,oi mm. at the ends. — Grun. Novara p. 21 PI. I f. 18. A. D. p. 51. 

 Per. IV f. 24 to 27. P. cestuarii var. CI. D. of Java II f. 19. P. (cquatnride CI. M. I). N:o 145, 

 146, 1878. P. inflafum Shade. T. M. S. II p. 16 PI. I f. 9 (1854)? 



Marine (pelagic): Balearic Islands! Sumatra! Java! New Zealand (Grun.). 



P. australe is very nearly connected Avith P. naviculaceum and with P. Normanii. 



25. P. Normanii Ralfs (1861). — V. gently sigmoid, lanceolate, with subacute ends. L. (),i3 

 to 0,22; B. 0,027 to 0,036 mm. Median line sigmoid, central. Transv. striae 19 to 21 in 0,oi mm. 

 Obi. strise 17 to 18 in the middle and 20 to 21 in 0,oi mm. at the ends. — Ralfs in Pritch. Inf. 

 p. 919. P. affme Grun. A. D. p. 51 (1880). V. H. Syn. PI. XVIII f. 9. Per. IV f. 5, 8. P. affine 

 var. Norm. Per. IV f. 6, 7. 



Marine: Spitsbergen! Davis Strait! North Sea! Mediterranean Sea! Red Sea! Java! Sumatra! 

 Samoa! Atlantic coast of North America! Colon! 



Var. fossilis Grun. (1880). — L. 0,i5 to 0,22; B. 0,o3 to 0,o35 mm. Transv. striae 17 in^O,oi 

 mm. Obi. strife 13 in the middle and 16 to 17 in 0,oi mm. at the ends. — P. affme var. fossilis 

 Grun. A. D. p. 51. Per IV f. 16 to 18. P. wr^/wmc^fw H. L. Smith (accord, to Perag.). F. (estuarii 

 var. intermedia Grun. Novara p. 102. P. neogradcnse Pant. Ill PI. XXI f. 315 (1893)? 



Marine (fossil): Virginia! Nankoori (Grun.). 



Var. marylandica Grun. (1880). — Rhomboidal-lanceolate, acute. L. 0,24 to O.as; B. 0,o3 to 

 0,044 mm. Transv. strite 14 to 18 in 0,oi mm. Obi. strife 13 to 17 in 0,oi mm. in the middle 

 and closer at the ends. — P. affine var. maryl. Grun. A. D. p. 51. Per. p. 10 PI. IV f. 15. 



Marine (fossil): Nottingham, Maryland! 



P. Normanii is one of the most common species, and connected with P. australe and P. stri- 

 gosmn, which latter has the same shape, and from which it may be distinguished by its median 

 oblifjuc striie, which cross each other at the angle of 90 and become acuter towards the ends. It 

 would be advisable to unite into one species P. naviculaceum, P. australe and P. Normanii. Peragallo 

 mentions a form called P. affine var inter rwpta (PI. IV f. 1, 2) which has an excenti'ic median line. 

 This form, as well as the specimen fig. 4, seems to me to be more akin to P. decorum var. dalmaticum. 



26. P. ailguliitum Quekett (1848). — V. rhomboidal-lanceolate, angular in the middle, with 

 acute ends. L. 0,i7 to 0,36; B. 0,036 to 0,or> mm. Median line central, slightly sigmoid. Central 

 nodule small, rhombic. Transv. and obi. stri;ie equidistant 18 to 22 in 0,oi ram. Angle 60°. — 

 Navic. angulata Quek. on the microscope p. 438 PI. VIII f. 4 to 7 (according to "W. Sm.). P.angu- 

 latum W. Sm. B. D. I p. 65 PI. XXI f. 205. V. H. Syn. p. 115 PL XVIII f. 2 to 4. Per. V f . 3 

 to 5. Nav. Thuringiaca KlJTZ. (according to Grunow). 



Marine: North Sea! Barbados! 



Forma undulata Grun. (1880). V. with slightly undulate margins. — Grun. A. D. p. 51. 

 Per. PL V f. 6. 



Marine: Bohusliln, Sweden! Belfast (Per.). 



