73 



gusta ; pagina interna tota alba; crenae in margine 

 ventris crassae^, umbones versus sensim diminutae ad 

 minorem modum redaetae, postremo evanescentes ; epi- 

 dermis atrofusca, holosericea ut in Pectunculo piloso L. 

 — Lono;. testae 49 — 50 niill. Lonc;. alt. et crass. ratio 

 bis circiter numeris respondet: 100, 85, 50. 

 23. Plicatula cuneata Dkr. 



Testa parva solidula, cuneato trigona paene aequi- 

 valvis, umbones versus valde attenuata, costis senis vel 

 septenis crassis interstitiisque obsolete imbricatis instructa, 

 albida, strigis flammisque fulvis picturata. — Alt. 13 — 

 14, long. 9—10 mill. 



24. Plicatula rugosa Dkr, 



Testa oblougo-ovata, umbones versus subattenuata, 

 inaequi^'alvis; valva superior plana imo subconcava, alba 

 fusco variegata, inferior convexa, tota alba, val\a utraque 

 plicis irregularibus rugosis, passira imbricatis instructa; 

 umbones dextrorsum involuti. — Alt. 34 mill. lat. 20, 

 crass, 11 mill. 



25, Tapes Greeffei Dkr. 



Testa ovato-elliptica, ventrosa, antice subattenuata, 

 postice paullo obtusior, in margine ventris regulariter 

 modiceque arcuata, costis crassis rotundatis, nonnullis 

 antice dicliotomis cincta; costae in utroque latere postico 

 abrupte evanidae, ad aream vero fortiter expressae; 

 umbones tumidi laeves ; Junula areaque lanceolatae, parum 

 distinctae; ligamentum angustum submersum. Color et 

 pictura variabiles; in fundo rubente, rarius roseo strigis 

 fuscis vel castaneis, interdum nio-rescentibus, anjjulatis 

 vel flexuosis et subreticulatis radiisque macularum irre- 

 gularium quaternis plus jninusve vividis variegata est 

 conclia. Pagina interna alba, interdum subrosea vel 

 pallide rufescens. Sinus pallii magnus linguaeformis. 

 Epidermis pallide cornea tenuissima sed firma- -^ Testae 



