KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 193 



central; its terminal fissures laterally expanded. Axial area indistinct; central area rounded- 

 quadrate. Alveoli disposed in oblique and traiisverse rows, the latter curved and slightly radiate, 

 10 in 0,0 1 mm. - Nar. cleps. Donk. M. J, I n. s. p. 8 Pl. I f. 3. B. D. p. fi3 Pl. X f. 2. A. S. 

 Atl. XL VIII f. 7—8 (no name). 



Marine, aestiiaries: Coasts of Scotland and England! Cape Horn (P. Petit). 



Var. scotica A. S. (1876). — Smaller, more linear. L. 0,o85 to 0, 09; B. O,oir, mm. — Nav. 

 scotica A. S. Atl. XL VIII f. 9-11. Cl. M. D. N:o 303. 



Marine: Scotland! 



4. T. Debyi Ledd. Fortm. (1892). — V. linear-lanceolate, convex, gradually tapering towards 

 the obtuse ends. L. 0,i.^ to 0,3o; B. 0, 025 to 0,o4 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 striffi about 20 in 0,oi mm. — Nav. cle2)sijdra A. S. Atl. XL VIII f. 39. 



Marine and brackish: Bed Sea! Sumatra (Grrove Coll.)! Java (Kinker Coll.)! Singapore! China 

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



Var. osculifera Cl. — Axial area unilateral; central area witli a linear marking on both 

 sides of the central nodule. — Alloioneis Debyi Leud. Fortm. I), de la Malaisie p. 18 Pl. II f. 5. 



There can be no donbt that T. Clexmjdra and T. Dehyi are distinct species. The fig. 38 in 

 A. S. Atl., {Nav. clejjs. var.?) appears to be a variety of T. aspera, or perliaps a new species. 



5. T. Johnsoninna (tREV. (1863). — V. elliptic-lanceolate, with obtiise or subrostrate ends. 

 L. 0,09 to 0,11; B. 0,03.3 to 0,037 mm. Axial area indistinct; central area, large, widened and 

 rounded outwards. Alveoli disposed in longitudinal and transverse rows; the former about 6 in 

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

 mm. — Nav. Johns. Grev. T. M. S. XI p. 17 Pl. I f. 8. Nav. Siehohlii Pant. III Pl. XX f. 293 

 (1893)? Trach. Johns. Icon. n. Pl. III f. 38. 



Marine: Java (I>eby Coll.)! Queensland (Grrev.), Port Jackson! New Zealand (Grev.), Japan, 

 Sendai Dept (Brun Coll.)! 



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

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

 T. Johnsoniana is closely connected with T. aspera. 



6. T. Bnmii Cl. (1891). — V. broadly elliptical. L. O.oes; B. 0,o34 mm. Axial area indi- 

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

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

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

 about 26 in 0,oi mm. — Nar. Brunii Cl. in Brun D. espéces 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 this form, unknown to me, has not the large central area of T. Brunii. It seems, 

 nevertheless, probable that Nav. 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 0,032 mm. Median Iine 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. — Alloioneis {Naricula?) Antillarmn 

 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. Handl. BaDd 26. N:o 2. 25 



