KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 35. N:0 5. 57 



Rhizosolenia (Guinardia?) recta Cl. ^ 



(Pl. VIII, fig. 7 a, b). 



Cellules cylindrical straight. Valve flat, more silicious than the zone, with a short 

 spine and a furrow for the reception of the spine of another frustule. Zone with nurae- 

 rous parallel falcral ribs, Avhich meet in a line parallel with the pervalval axis. Chro- 

 matophores elongated, numerous. Nucleus parietal. Pervalval axis 0,08 to 0,i6; transverse 

 and sagittal axis 0,022 mm. 



Streptottieca maxima Cl. n. sp. 



(Pl. VIII, fig. 5). 



There were found in some samples a verv large form, Avhich seems to be akin to 

 Streptotheca thamesis. The frustules are scarcely twisted, exceedingly thin-Avalled and 

 their membrane becomes strongly dyed by methyle-green. The membrane persists after 

 ignition and shows very faint parallel division-lines. 



The chromatophores are numerous and rounded. The nucleus is central. 



Length of the sagittal and pervahal axes 0,2 rnm. 



Thalassiosira Aurivillii Cl. n. sp. 



(Pl. VIII, lig. :;). 



Valve with aljout 12 peripherical small nodules. The alveoli are arranged in radiate 

 lines (about 26 in 0,oi mm.) which are grouped in a fasciculate manner. There are about 

 12 fasciculi, each with about 8 rows of alveoli. The part of the valvo, which is 

 parallel with the pervalval axis, carries close, but sharp, stria:^ parallel to the said axis, 

 and about 27 in 0,oi mm. 



The frustules are coherent in long chains probably by means of slirae-threads, but 

 1 did not succeed in seing them. To judge from a carbonized specimen there seera to 

 be several marginal threads, issuing from the marginal small nodules, but this requires 

 further examination. 



Pervalval axis 0,oi7, sagittal and transverse axis 0,027 mm. 



Litoral diatoms. 



Auricula punctata (Pantocz.). 



(Pl. VIII, fig. 6). ' 



It is with much hesitation I refer to this species, found in a fossil state in Hungaria 

 {Amphiprorn pun.ctata Pantocz., Fo.ss. Bacill. Ungarns Part. III, 1892, Pl. XXXIX, fig. 547), 

 a valve met Avith in a sample from Billiton. The sagittal axis measnred in length 0, 1.5 mm. 

 The valve Avas centrally strongly constricted and covered AAath a number of inordinate 

 puncta, tOAvards the median line arranged in roAVS parallel to the said line. 



^ This species bas been described by Ostenfeld under tho name of CcratauKna rompaeta (Vidcnsknbl. 

 Mcddel. fra den Naturh. Förening KbhAni 1901, p. 153). OSTENFELDS namc therefore bas priority. 



K. Sv. Vet. Atad. Handl. Band 35. N:o 5. 8 



