90 Pelecypoda. — Arcacea. 



cussata; umbones ad ^'2 — ^/3 long. siti, paullo incurvi; area angusta; cardo 

 antice denticulis 5, postice 10 munitus. — Long. 9 mm, alt. 6 mm. 



D i s t r i b. : Atlanticum. 



Habit. : Marseille, la Cassidagne, Peyssonel (Maeion); prof. 214 — 609 org. 

 inter Sardiniam et Neapolim („Wasliington", Giglioli); „Adventure Bank" (Jefp- 

 BEYs) ; Palermo, prom. S. Vito, Sciacca (Monterosato), Messina (Seguexza) ; ad 

 insulas maris Aegei (Jeffreys). 



10. Arca pectunculoides Scacchi (A. raridentata S. Wood). Testa minuta, 

 modice convexa, oblique rotundata, paullo longior quam altior, antice angustior, 

 postice paullo expansa , margine libero arcum aequum formante , cardinali recto 

 utrinque angulato ; umbones pauUo ante mediura siti-, parvi sed prominuli , area 

 angusta; valvae subtenues, paullo inaequales, lineis tenuibus elevatis radiantibus 

 et concentricis subtiliter decussatae , epidermide tenui cinereo-fulvescente pilis 

 brevissimis per lineas radiantes dispositis ornata ; denticulis cardinalibus auticis 

 3 — 4, posticis 4 — 5 valde obliquis fere longitudinalibus. — Long. 5 mm. 



Var. septemtrionalis Jeffr. Major, magis trigona et obliqua, striis 

 tenuibus longitudinalibus, non reticulata. 



Distrib. : Atlanticum boreale ; sinus Caribaeus. — Fossilis in stratis 

 tertiariis. 



Habit. : 20 — llTOorg. prof. ; Gibraltar (McAndrew); Cartagena (Jeff- 

 reys) ; Alger, Benzert (Jeffreys); Marseille, Peyssonel (Marion), Toulon (Lo- 

 cabd) ; Napoli (Acton); Sicilia : prom. S. Vito , Sciacca (Monteeosato) ; prof. 

 337 — 464 org. inter Sardiniam et Neapolim („Washington", Giglioli, var. septem- 

 trionalis) ; „Adventure Bank" (Jeffrkys) ; ad insulas maris Aegei (Jeffreys). 



m 11. A. Weinkauffi Crosse. Testa rhomboidea, Arc. diluvii similis, sed 

 area multo majore fere quadrata, umbonibus magis distantibus, crassitudine longi- 

 tudinem et altitudinem superante. — Long. 25 mm, crass. 30 mm. 



Habit. : Alger, rara (Weinkauff). 



m ? 12. A. minuta Desh. (necL.?). „Testa oblonga, transversa, quadri- 

 latera, inaequilatera, longitudinaliter costata, costis rotundatis, simplicibus, aequa- 

 libus; cardine recto, multidentato ; dentibus posticalibus obliquis." — Long. 3 mm^ 

 lat. 5 mm. — An forma juvenis alius speciei? 



Habit. : In arena, Morea (Deshayes, ,Expedition'). 



Pectunculus Lam. Fallium apertum, margine postico ocellifero; pes magnus, 

 crassus, antice acutus, compressus; hranchiae aequales; palpi breves, oUiqui; hyssus 

 nullus; testa suhorhicidaris , aequivalvis, aequilatera, solidissima, epidcrmide vehitina 

 tecta, facie interna „porceUanea" ; umbones lcviter curvi, fere recti; ligamentum ex- 

 ternum, area distincta, sulcis divergentibus; margo cardinalis regulariter arcuatus aut 

 semicircularis ; dentes breves, fortes, numerosi, mediis in adultis obsolctis; margines 

 crenulati. 



Nom. vulg. spec. : Napoli : Palorda (0. G. Costa). 



1. P. glycymeris Forr. et Hly. (Arca glycijmtris et pilosa L. , P. mar- 

 moratus Lam., P. stcllatus Phil., P. Jiammidatus Een. , Axinea glgcymeris Brus.). 

 Testa suborbicularis, leviter compressa, solidissima, striis radiantibus subtilissimis 

 lineisque compressis concentricis sculpta, sub epidermide crassa fusca in junioribus 

 ciliosa lutescenti-albida, purpureo-fusco maculata et fulgurata; umbones parvi pro- 

 minuli; ligamentum fuscum, fasciculis 8 — 9; cardo percrassus "/7 ambitus occupans, 

 dentibus antice et postice 6 — 7 majoribus ; facies interna lutescens, interdum 

 purpureo diffuse tincta. — Diam. 60 — 80 mm. 



Distrib. : Atlanticum ; Japonicum. 



