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



(5 to 8 in 0,01 mm.), coarsely, transversely striate; strise 8 to 9 in 0,oi mm. On both sides of 

 the longitudinal margins is a broad hyaline limbns. V. narrow, linear, with broad capitate ends. 

 Median line slightly biarcuate. Dorsal side with 8 strise in 0,oi mm., coarsely but obscurely 

 punctate. Ventral side without striae, and with a longitudinal line close to the median line. — 

 Diatomiste I p. 159 PL XXIIl f. 1, 2. 



Marine: Norway, Grip! Morocco! Balearic Islands! Macassar Straits! Galapagos Islands! 



The frustule has a considerable resemblance to A. exsecta Gkun., but the valves are diffe- 

 rent. A. limpida Jan. (A. S. Atl. XXXIX f. 8) is probably allied with this species, or is perhaps 

 a small variety of it, but the figure it not sufficient for identification. 



6. A. sendaiana Brun (1891). — V. linear with obliquely rounded ends. L. 0,19; B. 0,02 

 mm. Median line biarcuate. Central nodule strong, dilated on the dorsal side to a stauros. iDorsal 

 side with 11, finely punctate strise in 0,oi mm. Ventral side without striae, and with a longitu- 

 dinal line. — D. especes nov. p. 9 PL XII f. 1. 



Marine: Japan, fossil! 



According to Prof. Brun there is a line across the striae, which I have not noted in an 

 original specimen, sent by him. If this line be not the margin of the frustule, and really crosses 

 the striae, this species may be removed from this group and placed in Diplamphora. 



7. A. GroTei Cl. (1892). — Frustule, of rectangular outline, gibbous on the back. L. 0,105; 

 B. 0,05 mm. Zone with several divisions, transversely striate; striae 18 in 0,oi mm. V. linear, 

 with gibbous dorsal margin and broad ends. L. 0,io to 0,12; B. 0,oi5 mm. Striae on the dorsal 

 side 10 to 11 in 0,oi mm., finely punctate. Ventral side not striate and with a longitudinal line. 

 — Diatomiste I p. 158 PL XXII f. 16, 17. 



Marine: Seychelles! Java! Sumbava (Kinker Coll.)! China! Macassar Straits! 



8. A. formcsa Cl. (1875). — Frustule rectangular with rounded angles. L. 0,i4; B. 0,o7 

 mm. Zone with few, broad divisions, about 12 in 0,oi mm., finely transversely striate; striae 8 to 

 9 in 0,01 mm. V. linear with obliquely rounded, spathulate, or clavate ends, according to the 

 position of the valve. L. 0,09 to 0,2; B. 0,025 to 0,035 mm. Median line biarcuate. Dorsal side 

 with 8 to 9 costate striae in 0,oi mm., alternating with more or less distinct puncta, 15 to 18 

 in 0,01 mm. Ventral side structureless, with a longitudinal line. — A. S. Atl. XXVIII f. 34, 

 XXXIX f. 2. A. Studeri Janisch A. S. Atl. XXXIX f. 1 (1876). 



Marine: Mediterranean Sea (Balearic Islands, Gulf of Naples)! Madagascar (Kinker Coll.)! 

 Ceylon (Colombo, Le Tourneur Coll.)! Sumatra (Deby Coll.)! Singapore! Sumbava (Kinker Coll.)! 

 Macassar Straits! Galapagos Islands! Colon (Deby Coll.)! Fossil: S:ta Monica, Calif. 



Var. minuta Cl. — L. of the frustule 0,085; B. 0,045 mm. Costae 9 in 0,oi mm. 



Marine: Macassar Straits! Bahia (Deby Coll.)! 



The valves of this very large and beautiful diatom have a very different shape according 

 to the position. A. Fetiti Leud. Fortm. (De de la Malaisie p. 10 PL I f. 3) may be a small form 

 of this species, which I am unable to decide without original specimens. 



9. A. Scala Cl. and Grovb (1892). — Frustule of rectangular outline, with slightly concave 

 sides and rounded ends. L. 0,i4; B. 0,05 mm. Zone with broad divisions (about 2 in 0,oi mm.) 

 which are transversely costate (costae about 5,5 in 0,oi mm.). V. in B. 0,oi5 mm. Dorsal side 

 with smooth, costate striae, 5 to 6 in 0,oi mm.; intermediate space not distinctly punctate. Ven- 

 tral side smooth with a strong longitudinal line. — Diatomist^ I p. 158 PL XXII f. 18, 19. 



Marine: Macassar Straits! Porto Seguro (Deby Coll.)! 



Var. alata Cl. — Dorsal side of the valve with a hyaline limbus. L. of the V. 0,24; 

 B. 0,018 mm. Striae 6 in 0,oi mm. 

 Marine: Macassar Straits! 



