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



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

 subacute ends. L. 0,3 6 to 0,4 6; B. 0,o62 to 0,o7 2 mm. Median line slightly sigmoid, central. Transv. 

 and obi. strise "/is in 0,oi mm. — GrRUN. A. D. p. 54. Per. p. 15 PI. VI f. I. 



Marine: Campeachy Bay (Grun.). 



This species is according to Pekagallo nothing but a variety of P. rigidum. 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 0,1 1 ; B. 0,017 mm. Median line central, sigmoid. Central nodule large, rounded. Median striae 

 more distant than the terminal. Transv. strise 21 to 23 in 0,oi mm.; obi. striae 18 to 20 in the 

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

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

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



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



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



25. P. ■Normanii Ralfs (1861). — V. gently sigmoid, lanceolate, with subacute ends. L. 0,i3 

 to 0,22; B. 0,027 to 0,036 mm. Median line sigmoid, central. Transv. strise 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. affine Grun. A. D. p. 51 (1880). V. H. Syn. PL 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. 0,1.5 to 0,22; B. 0,03 to 0,o35 mm. Transv. striae 17 in]_0, 01 

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

 Grun. A. D. p. 51. Per IV f. 16 to 18. P. virginiacum H. L. Smith (accord, to Perag.). . P. cestuarii 

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



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



Var. marylandica Grun. (1880). — Rhomboidal-lanceolate, acute. L. 0,24 to O.28; B. 0,o3 to 

 0,044 mm. Transv. strise 14 to 18 in 0,oi mm. Obi. strise 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 PL IV f. 15. 



Marine (fossil): Nottingham, Maryland! 



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

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

 oblique strise, 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. Pbragallo 

 mentions a form called P. affine var interrupta (PL IV f. 1, 2) which has an excentric 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. angulatum Quekett (1848). — V. rhomboidal-lanceolate, angular in the middle, with 

 acute ends. L. 0,i7 to 0,36; B. 0,036 to 0,05 mm. Median line central, slightly sigmoid. Central 



nodule small, rhombic. Transv. and obi. strise equidistant 18 to 22 in 0,oi mm. Angle 60°. 



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

 latum W. Sm. B. D. 1 p. 65 PL XXI f. 205. V. H. Syn. p. 115 PL XVIII f. 2 to 4. Per. V f. 3 

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



Marine: North Sea! Barbados! 



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

 Per. PL V f. 6. 



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



