KONGL. SV. Virr. AKADEMIENS HANDLINOAR. RAM) 26. N:(t 2. 193 



central; its terminal fissures laterally ex-|)ande(l. Axial area indistinct; central area roiinded- 

 qnadrate. Alveoli disposed in oblique and transverse rows, tlie latter curved and slightly radiate, 

 10 in 0,0 1 mm. — Nar. deps. DoNK. M. J I n. s. p. 8 PL I f. H. B. 1). p. ()3 PI. X f. 2. A. S. 

 Atl. XLVIII f. 7-8 (no name). 



Marine, aestuaries: Coasts of Scotland and England! ('a])e Horn (P. I'etit). 



Var. srotica A. S. (187()). — Smaller, more linear. L. 0,08:) to 0,0'.); B. 0.oi5 mm. — Nav. 

 srotica A. S. Atl. XLVIII f. i)— 11. Cl. M. I). N:o 303. 



Marine: Scotland! 



4. T. Debyi Leud. Fortm. (1892). — V. linear-lanceolate, convex, gradually tapering towai'ds 

 the obtuse ends. L. O,!.") to 0,.3o; B. 0,02.5 to 0,04 mm. Axial area narrow linear, symmetrical; 

 central area orbicular. Alveoli disposed in oblique and transverse rows, the latter parallel, 8—9 

 in 0,01 mm. Longitudinal fine stricB aliout 20 in 0,oi mm. — Nav. cJeps:y<lra A. S. Atl. XLVIII f. 39. 



Marine and brackish: Red Sea! Sumatra ((rrove Coll.)! Java (Kinker Coll.)! Singapore! China 

 (Penang Harbour Dr. Rae Coll.)! Australia (St. Vincent, Atl.)! 



Var. nscidifera Cl. — Axial area unilateral; central area with a linear marking on both 

 sides of the central nodule. — AUoioncis Dehyi Leud. Fortm. D. de la Malaisie p. 18 PI. II f. 5. 



There can be no doubt that T. Clepsydra and 1\ Debyi are distinct species. The fig. 38 in 

 A. S. Atl., (Xav. clcps. var.?) appears to be a variety of T. asp)t'ra, or pei^haps a new species. 



f). T. Johiisoiiiiina TtREV. (1863). — V. elliptic-lanceolate, with obtuse or subrostrate ends. 

 L. 0,09 to 0,11; B. O.o;?.-? to 0,037 mm. Axial area indistinct; central area, large, widened and 

 rounded outwards. Alveoli disposed in longitudinal and transverse rows; the former about (i in 

 0,01 mm.; the latter radiate throughout, 8 — 10 in 0,oi mm. Longitudinal fine strise 25 in 0,oi 

 mm. — Nav. Johns. Grev. T. M. S. XI p. 17 PI. T f. 8. Nav. SiehoUlii Pant. Ill PI. XX f. 293 

 (1893)? Trach. Johns. Icon. n. PL III f. 3S. 



Marine: Java (Beby Coll.)! Queensland (drev.). Port Jackson! New Zealand ((jrrev.), Japan, 

 Sendai Dept (Brun Coll.)! 



The valve is sometimes slightly asymmetrical, the median line being excentric. The central 

 area, rounded in typical specimens, is in some varieties dilated and truncate outwards, so that 

 T. Johiisoniana is closely connected with T. aspcra. 



(>. T. Brimii Cl. (1891). — V. broadly elliptical. L. O.oes; B. 0,034 mm. Axial area indi- 

 stinct; central area large, transverse, rounded outwards. Alveoli disposed in two to three longi- 

 tudinal rows along the median line, in oblique rows towards the margin. Transverse rows of 

 alveoli slightly radiate throughout, 9 (middle) to 12 (ends) in 0,oi mm. Longitudinal fine strise 

 about 26 in 0,oi mm. — Nav. Brmui Cl. in Brun D. especes n. p. 33 PL XVI f. 4. 



Marine: Japan (Brun Coll.)! China! 



This species has some resemblance to Nav. Ovum Faschale (A. S. Atl. PL VIII f. 56) also 

 from Japan, but tliis form, unknown to me, has not the large central area of T. Brunii. It seems, 

 nevertheless, probable that N((v. Ovum Faschale is a form of Trachyneis. 



7. T. Antillaruni Cl. (1878). — V. linear-lanceolate to linear-elliptical, with obtuse ends. 

 L. 0,12 to 0,17; B. 0,026 to 0,0.32 mm. Median line somewhat excentric. Axial area more or less 

 broad, irregularly linear and unilateral. Central area rounded, unilateral, on the opposite side of 

 the axial area. Alveoli disposed in longitudinal flexuose or irregularly oblique rows. Trans- 

 verse rows slightly radiate throughout 9 to 10 in 0,oi mm. — AUoioncis (Navicula?) Antillantm 

 Cl. West. Ind. D. p. 8 PL II f. 11. 



Marine and brackish: Campeachy Bay! West Indies! Florida! Red Sea! Bab el Mandebi 

 Madagascar! Singapore! Java! Sumatra! China! 



K. Sv. Vet. Akad. Ilandl. Band 2(;. N:o 2. 25 



