MARINE DIATOMS OF THE PHILIPPINE ISLANDS 11 



verse at the center, increasingly radial toward the ends; a narrow 

 linear transverse stauros, no hyaline median area bordering the 

 rhaphe; upper valve wilh same beading as under valve. 



Length 0.039; w idth 0.012 ; 6 double lines in 0.01 mm. 



Type.— Cat. No. 43561, U.S.N. M. 



The shape of this new species is closely similar to that of A. sub- 

 sessilis Kutzing, which, however, like A. brevipes Kiitzing, has single 

 rows of beads without separating costae. The beading is like A. 

 longipes, from which it differs both in outline and in being, despite 

 its small size, a relatively much more massive diatom, with thick, heavy 

 frustules. It is also more coarsely beaded; thus for A. longipes with 

 a length of 0.2 mm. we have six double rows in 0.01 mm. (see De 

 Toni, Syl. Alg., p. 470) while here six rows are found on a valve of 

 only 0.039 mm. A. longipes occurs in the Philippines and the two are 

 unmistakably distinct. The species is abundant at Jolo Jolo, Sulu 

 Islands. It was not found elsewhere in the Philippine Islands. It, 

 however, occurs at the Laysan Islands, and has an average length of 

 about 0.04 mm. 



ACHNANTHES CRENULATA Grunow 



(Cleve and Grunow, Arct. Diat., p. 20; figure in Le Diatomiste, pi. 9, figs. 3-4.) 



The measurements of my specimen are: Length 0.079; width 0.018; 

 7 lines in 0.01 mm. 



ACHNANTHES HETEROMORPHA Grunow 



(According to Cleve in Schmidt, Atlas, pi. 198, figs. 52-58.) 

 This might be better classified as Cocconeis. Its resemblance to 

 A. lanceolata (Brebisson) Grunow may be responsible for placing it 

 under AcJinanthes. It has no trace of bend in the girdle view in any 

 of the specimens I have examined. It has some likeness to A. jla- 

 haulti Heribaud (Diat. foss d'Auverg., 1903, pi. 10, figs. 17-18) except 

 for the stauros. 



ACHNANTHES HEXAGONA Brun and Cleve 



(Brun, Espec. Nouv., p. 5, pi. 19, figs. 3a-b.) 



ACHNANTHES INFLATA (Kutzing) Grunow 



(Grunow, Reise, F. Novara, p. 98.) 



It is Ehrenberg's A. ventricosa (1854) (not Kutzing, 1844), and is 

 well figured in Ehrenberg's Mikrogeologie (pi. 3, figs. 18-19). 



ACHNANTHES LONGIPES Agardh 



(Smith, Brit. Diat., pi. 36, fig. 300.) 



ACHNANTHES TENUISTAUROS, new species 



Plate 1, figs. 3-6 



Valves very broadly fusiform, sometimes very broadly oval; ends 

 acuminate, rounded ; under valve with markings of double rows of 

 beading with separating costal lines, strongly radiating; median area 



