— 413 — 



Arca scabra Poli Test Sicil. II T. 25, F. 22. - Philippi Enum. I 

 p. 58. — Weinkauff Mittelm. p. 199. 

 Hab. mare mediteiTaneum, corallis atfixa. 



6. Arca imbricata Poli. T. ovato-oblonga, postice 

 oblique truncata, angulata, albida, squamis imbricatis approxi- 

 matis per series concentricas regulariter dispositis, marginem 

 ventralem versus apertis peculiariter sculpta ; umbonibus approxi- 

 matis; cardo dentibus paucis, lateralibus majoribus, intermediis 

 fere obsoletis munitus ; margo duplex, interior crenulatus, exterior 

 a squamarum serie ultima formatus. - Long. 12, alt. 8 Mm. 



Arca imbricata Poli Test. Sicil II T. 25, F. 10. 11. — Philippi 



Enum. I p. 58. — Weinkauff Mittelra. p. 200. 

 Arca clathrata Defrance Dict. sc. uat. II Suppl. p. 115. — Lam. VI 



p. 478. 

 ? Arca pulchella Eeeve Conch. icon. sp, 122. — Locarcl Cat. p. 481. 



— Monterosato Enum. e Sin. p. 7. 



Hab. mare mediterraneum, corallis affixa. 



7. Arca nodulosa Miiller. T. modice convexa, ante 

 medium leviter constricta, oblonga vel oblique subrhomboidea, 

 duplo longior quam altior, valde inaequilatera, antice angustata 

 et breviter rotundata, postice dilatata et oblique truncata, 

 margine ventrali obliquo medio leviter inttexo; dorsali recto 

 utrinque distincte angulato, angulo posteriore sat prominente et 

 compresso, umbonibus in ^4 anteriore sitis, magnis et tumidis, 

 area ligamentali subrhomboidea ; valvulae solidulae, noduloso- 

 decussatae, epidermide fusca margines versus squamoso-lacera 

 tectae, denticulis cardinahbus lamellosis obliquis , anticis cir- 

 citer 7, posticis circiter 13. — Long. 15 Mm. Sars. 



Arca noclulosa MiUIer Zoolog. Dan. Prodr p. 247 — Jeffreys Br. 

 Conch. II p. 180 T. 100, F. 2. - Sars Norveg. p 42 T. 4, F. 3. - 

 Jeffreys Pr. Z. S. 1879 p. 570. 

 Hab. mare boreale. 



8. Arca obliqua Philippi. T. ovato-oblonga, trans- 

 versa, valde inaequilatera, antice angustior, postice oblique 

 truncato-rotundata, striis exilibus radiantibus, concentricisque 

 irregularibus decussata; apices ad ^l^— 'Is long. siti, parum 

 incurvi; area angusta; cardo antice denticulis 5, postice 10 muni- 

 tus. — Long. 9, alt. 6 Mm. Philippi. 



Arca obliqua Philippi Enum. II p. 43 T. 15, F. 2. — Jeffreys Br. 



Conch. II p. 175 T. 80, F. 4. - Pr. Z. S. 1879 p. 572. — Mou- 



terosato Enum. e Sin. p. 7. 

 Arca Koreni Danielssen lide Monterosato Eu. e i^in. p. 7. 



Hab. in aqua profundiore maris atlantici et mediterranei. 



9. Arca glacialis Gray. T. sat tumida, oblongo-sub- 

 rhomboidea, antice quam postice humilior, margine ventrali et 

 antico arcum aequum formantibus, postico oblique truncato, dorsali 

 recto utrinque distincte angulato, umbonibus sat magnis, pro- 

 minentibus in Vp antica sitis; valvulae solidulae lineis concen- 

 tricis et radiantibus subtiliter decussatae, epidermide fuscata 



