KONGL, SV. VKT. AKADiailKNS IIANDMNGAR. RANI) 27. N:() 3. 108 



Tliis little form scarcely belongs to A. ovalis and is remarkable for the strongly striate 

 dorsal and ventral sides, as well as for the absence of central area. Perhaps a small form of 

 the following. A. Frotcns rar. parvula Flogel Pommerania Exp. j). «!) f. 10 may repre.sent 

 this form. 



7. A. marina (\V. Sm. 1857?) V. H. (1880). — Frn.stule in outline elliptical or orbicular, 

 with trnncate ends. L. 0,04; B. O^oi:, mm. V. Inneate, with subacute ends and slightly concave 

 ventral margin. L. 0,04 to 0,06; B. (),oi to 0,0 i:i mm. Median line slightly biarcnate. Axial and 

 central areas not distinct on the dorsal side. Stripe 15 in 0,oi mm. coai-sely ])unctate, not inter- 

 rupted or crossed by a longitudinal line. Ventral side narrow, striate as the dorsal side. — 

 A. N. H. 1857 p. 7 PI. I f. 2? V. H. Syn. p. 58 PI. I f. K!. A. S. Atl. XXVI I f. 14, 17, 18. 

 A. pellucida Greg. D. of Clyde p. 513 PL XII f. 73? A. nana Flogel Pommerania Exp. p. 90 f. 12? 



Marine: North Sea! Balearic Islands! Seychelles! China! Porto Seguro (Deby Coll.)! 



A. marina of W. Sm. is too badly figured for identification. According to Ahnott (M. J. 

 VI p. 20(j) A. marina is identical with A. Protcns of Greg., but if so the stripe are incorrectly 

 stated as 40 in 0,ooi". A. 'pcUnrida Greg, is too imperfectly described and figured for admitting 

 of identification, but it seems to be the same as A.- marina. A. marina is doubtful as a species, 

 probably a form of A. Proteus. 



8. A. Proteus Greg. (1857). — Frustule elliptical with truncate ends, about twice as long 

 as broad. Valve lunate, obtuse. L. 0,o4 to 0,o65; B. 0,oo.5 to 0,oi6 mm. Median line biarcuate. 

 Axial area indistinct on the dorsal side. No central area. Striaj on the dorsal side 9 to 13 in 

 0,0 1 mm. not interrupted and coarsely punctate. Ventral side striate, especially towards the ends. 

 Striffi radiate, approximate to the median line and crossed by a narrow, blank band. — D. of Clyde 

 p. 518 PL XIII f. 81. A. S. Atl. XXVII f. 3. A. Prof. var. Kariana Grun. A. D. p. 24 PL I 

 f. 7 (1880). A. hexagonalis 0. Witt Mus. GodefFroi I p. %Q PL VIII f. 12? A. speciosa Castr. 

 Voyage Challenger p." 17 PL XXVII f. 1? 



Marine: Greenland! Spitsbergen! Finmark! Sea of Kara! Cape Deschneff! North Sea! S:t 

 Helena! Campeachy Bay! Mediterranean Sea! Black Sea! Seychelles! China! Galapagos Islands! 



Var. contigua Cl. — Strite on the ventral side not crossed by a blank, narrow band. — 

 A. S. Atl. XXVII f. 7 to 9. Probably also XXVIII f. 4. 



Marine: North Sea! Adriatic! Labuan! New Caledonia! 



Var. alata Cl. — V. L. 0,13; B. 0,o32 mm. Dorsal side with a projecting hyaline limbus 

 in the middle. Striffi 12 in 0,oi mm. 



Marine: Baltjic Dept. (Van Heurck Coll.)! 



9. A. robusta Greg. (1857). — Frustule in outline broadly elliptical, with truncate ends. 

 L. 0,06') to n, 1;; B. 0,038 to 0,12 mm. Valve lunate with arcuate dorsal margin and straight 

 ventral margin. Median line strongly biarcuate. Axial and central area indistinct on the dorsal 

 side. Dorsal side with strong stripe, (i to 7 in 0,oi mm, not crossed by a longitudinal line, 

 coarsely punctate; puncta about 8 in 0,oi mm. Ventral side broad, with a more or less broad 

 band of coarse radiate stripe along the median line. — D. of Clyde p. 51(5 PL XIII f. 79. 



Marine: Spitsbergen (stripe 10 in 0,oi mm.)! North Sea! Mediterranean Sea! Adriatic! Ma- 

 cassar Straits! Japan (fossil)! Samoa! 



Var. fiisca Cl. — Connecting zone with a number of small, irregular puncta, giving it a 

 brownish coloi;r. L. 0,12; B. 0,o75 mm. Stri.e (5 in 0,oi mm. 



Marine: China (Deby Coll.)! 



Var. suhjjlicata Cl. — Connecting zone with traces of longitudinal divisions and longitudinal 

 rows of puncta. L. 0,iir); B. 0,04.'j mm. Stripe 8 in 0,oi mm. 



Marine: S:ta Monica, Cal. fossil (Deby Coll.)! 



