. Bulletin of the British Museum (Natural History), Botany. 28 R. ROSS longitudinales c. 18 in 10 ^,m dispositae; areolae ad marginem frontis non attingentes sed taenia iiyalina c. 2 ^.m lata secus marginem. Periplekton caule circulari diametro ixm, 10-12 |xm alto, recto, ad eum valvae fraternae appresso, annulo subquadrato diametro c. 12 (jim periplekton valvae fraternae arete amplectenti, ex brachiis duobus aequalibus constanti; brachia longe imbricata, ubi superposita angustatissima, ad fines paene approximata. Ocelli diametro c. 8 [xm, transversi, fere verticales, porellis 40-45 in 1
. Bulletin of the British Museum (Natural History), Botany. 28 R. ROSS longitudinales c. 18 in 10 ^,m dispositae; areolae ad marginem frontis non attingentes sed taenia iiyalina c. 2 ^.m lata secus marginem. Periplekton caule circulari diametro ixm, 10-12 |xm alto, recto, ad eum valvae fraternae appresso, annulo subquadrato diametro c. 12 (jim periplekton valvae fraternae arete amplectenti, ex brachiis duobus aequalibus constanti; brachia longe imbricata, ubi superposita angustatissima, ad fines paene approximata. Ocelli diametro c. 8 [xm, transversi, fere verticales, porellis 40-45 in 10 |xm. Spinae marginales crassae, ad apices fere attingentes, c. 12 |xm altae, in portione centrali valvae in 10 ixm, super expansae atque intricatae et ad basim tuberculo minimo instructae, in projecturis distantiores et acutae. Spinae super- ficiales nullae. Cingulum ex quatuor minimum taeniis con- stans; valvocopula parte interiori hyalina c. (xm alta et parte exteriori c. 7 ixm alta sed apicem clausum versus decrescens et 4 |xm alta; copula II parte exteriori c. 5 |xm alta; copula III parte exteriori c. 4 [xm alta; copula IV parte exteriori c. 2 (xm alta; copulae II-IV quaeque ligula bene evoluta instructa; partes exteriores copularum omnium striis verticalibus 25-30 in 10 |xm ex areolis 18-25 in 10 jxm constantibus instructae. Typus. BM 78360 ex stratis eocaenicis ad 'Kamichev', Ros- siam. Valves not depressed at the centre, with flat-topped apical elevations c. 5 tall, c. 10 (xm long; valves 95-310 jxm long, 25-50 |xm wide, with an elongate elliptical central portion, and relatively broad and sometimes subcapitate projections rounded at the apices, the projections (xm wide, expanding to 10-18 M-m wide at their tips when these are subcapitate. Mantle separated from the valve face by a sharp angle, vertical, c. 4 ^xm deep, hyaline. Central area elliptical, its breadth about half that of the valve. Areolae c. jxm in diameter, in radial striae in the
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Keywords: ., bhlconsortium, bookcentury1900, bookcollectionbiodiversity, bookl
