KONGL. RV. VRT. AKADRMIRNS HANDLINGAR. BAND 27. N:o 3. 113 



akin to it. A. elongata GtREG. (D. of ('lyde p. 521 PI. XTII f. 84) seems to be an elongated 

 variety' of this species, which is nearly related to the following. 



15. A. Oraeflii (Grun. 1875) Cl. — Frnstule elliptical to rectangular, with broad, truncate 

 ends. L. 0,i; B. OjO.'^ mm. Zone with about 2 divisions in (),oi mm. striate; str'iic 17 in 0,01 mm. 

 V. lunate, with almost straight ventral margin and not protracted ends. 1j. (),i to ",i;i; B. 0,(ii:i 

 to 0,025 mm. Median line biaivuate. Axial area more or less broad on the doi'sal side. Striu; II 

 to 14 in 0,0 1 mm., not distinctly punctate, and crossed by a conspicous, narrow blank line. Ventral 

 side structureless or with a row of faint and short strife. No distinct longitudinal line. — A. 

 Gmi'fii var. A. S. Atl. XXV f. 40. A. truncata? Atl. XXVIII f. 5? A. Dehyi Leud. Fortm. D. 

 de la Malaisie p. 10 PI. I f. 4 (1892)? 



Marine: Gulf of Naples (Brun Coll.)! Zanzibar (Atl.), Sumatra (Deby Coll.)! China! (ia\a- 

 pagos Islands! 



A. Grceffil Grun. in A. S. Atl. is to judge from the figures the same species as A. Greril- 

 leana. At least I am not able to discover any distinctive characteristics. I understand A. Grceffii 

 to represent a form, nearly akin to A. Grevilleana but with closer, not distinctly punctate 

 striffi, and not protracted ends. The zones appear to differ in the divisions, which in A. Grrfffii 

 are contiguous, but in A. Grevilleana are separated by an intermediate, blank, longitudinal band. 

 This requires further investigation. 



Var. staurophora Cl. — Central nodule transversely dilated to a short stauros. 



Marine: Gulf of Naples (Brun Coll.)! 



16. A. Grevilleana Greg. (1857). — Frustule more or less rectangular, with truncate ends. 

 L. 0,1 to 0,16; B. 0,035 to 0,i mm. Zone with about 3 divisions in 0,oi mm. transversely striate ; 

 striai 6 to 17 in 0,oi mm. V. with arcuate dor.sal margin and more or less produced ends. L. 0,io 

 to 0,22; B. 0,02 to 0,03 mm. Median line biarcuate. Axial area more or less broad on the dorsal 

 side. Dor.sal side with 6 to 10 strise in 0,oi mm. Striit coarsely punctate, crossed by a distinct 

 longitudinal line or keel. Ventral side structureless, with a strong longitudinal line. — T. M. S. 

 V. p. 73 PL I f. 36. D. of Clyde p. 522 PI. XIII f. 89. A. S. Atl. XXV f. 41. A. sulcata Greg. 

 D. of Clyde PI. XIII f. 92? A. complexa Greg. 1. c. f. 90. A. fasciata Greg. 1. c. f. 91. A. Grmffii 

 Grun. A. S. Atl. XXV f. 42 (1875). A. Grev. var. prominens Grun. A. S. Atl. XXV f. 43, 44. 

 Var. camjjechiana Grun. 1. c. f. 45. A. (Grerill. var.?) sepidta Pant. I p. 22 PL XXIV f. 223 

 (1886). A. sumatrensis Leud. Fortm. D. de la Malaisie p. 10 PL I f . 5 (1892)? 



Marine: Spitsbergen (small form L. 0, 1 mm. Striae 12 on the valve, 17 on the zone in 0,oi 

 mm.)! North Sea! (Tuernsey! Morocco! Gulf of Naples! China! Magellans Strait! S:ta Monica 

 Calif., foss. (Deby Coll.)! Galapagos Islands! Campeachy Bay (Atl.). 



A. Grevilleana is a somewhat variable species, closely connected with A. Grceffii, from which 

 it is distinguished by larger size, more j^rominent ends and the coarsely punctate strise. On larger 

 specimens the latter seem under high power to be costate and alternate with double rows of puncta 

 (about 9 in 0,oi mm.). 



Var. contracta Cl. — V. with straight ventral, and in the middle deeply sinuose dorsal 

 margin. Ends rostrate-capitate. L. 0,o85 to 0,125; B. 0,02 to 0,o28 mm. Median line almost 

 straight. Axial area moderately wide on the dorsal side. Strise 8 in 0,oi mm., ccstate and alter- 

 nating with double rows of puncta, 13 in 0,oi mm. Keel across the strise strong. Ventral side 

 narrow. — A. S. Atl. PL XL f. 33. 



Marine: Barcelona! Grip, Norway (Atl.). 



17. A. prohoscidea (Greg. 1857?) Cl. — Frustule elliptical, with truncate ends. L. O.oes 

 to 0,07; B. 0,034 mm. Zone with 3 .sharply defined divisions in 0,oi mm., transversely striate; 

 striie about 10 in 0,oi mm. V. with rostrate and incurved ends. Median line biarcuate. Axial 



K. Sv. Vet. Akad. Handl. Band 27. N;o 3. 15 



