— 309 — 



4. Mactra subtruncata Montagu. T. ovato-trigona 

 vel regulariter trigona, subaequilateralis , concentrice striata, 

 lateribus sulcatis, alba, epidermide tiavidula iuduta; marginibus 

 acutis; latere antico rotundato-subangulato, postico subrostrato, 

 parum liiante, angulato ; margine frontali declivi, ventraii medio 

 subplano; umbones crassiusculi lateraliter depressi, acuti, parum 

 curvati, approximati, lunula distincta elongato-cordata, sulcata, 

 medio elevata; area angulis circumscripta concavo-convexa, sul- 

 cata; intus alba, sinus pallii minutus, obliquus, rotundatus. — 

 Diam. 25 Mm. Weinkauff. 



lilactra subtruncata Montagu Test Br. p. 92. — Forbes et Hanley 

 I T. 22, F. 8. - Reeve sp. 90. - Jelfreys Br. Conch. II p. 419 

 T. 43, P. 3 — M. Ch. II T. 11, F. 7. 8. — Sars Norv. p. 72. 

 Var. = Mactra triangula Reuier Tav. alf. — Brocchi Foss. subapp. 

 p 536 T. 13, F. 7. — Hidalgo Esp. T. 30, F. 3. 4. - Weinkauif 

 Mittelm. p. 48. — Reeve sp. 94. - Chenu Man. F 233. 

 Hab. e Mediterraneo usque ad Norvegiam. 



5. Mactra elliptica Bro w n. T. subcompressa, elliptico- 

 triangularis, fere aequilatera, utrinque producta et inferne sub- 

 angulata, extr. postica paulo angustiore, antica oblique subtrun- 

 cata, margine ventrali leviter arcuato, dorsali utrinque fere 

 aequaliter declivi, umbonibus parum prominulis, paulo ante 

 medium sitis; ligamento minimo et obscuro; valvulae plus 

 minusve solidae, albido-tlavescentes, sublaeves, striis incrementi 

 irregularibus, cardine sat forli, dentibus primariis 2 approximatis, 

 lateralibus distinctissimis, fovea cardinalis obliqua sat magna. — 

 Long. 22 Mm. Sars. 



Mactra elliptica Brown III. Conch. T. 15, F. 6. — Forbes et Hanley I 

 p. 3.56 T. 22, F. 3. - Sow. 111. Ind. T. 3, F. 22. — Sars Norv. 

 p. 72. - Locard Cat. p. 401. 



Mactra solida var. Jelfreys Br. Conch. II p. 417. 



Hab. Oceanum atlanticum borealem. 



6. Mactra solida Linne. T. triangularis, convexa, 

 solidissima, striis concentricis ad margines et in dorso plerumque 

 lamellosis sculpta, vestigiis incrementi distinctissimis, lutescenti- 

 alba, epidermide fuscescente plerumque detrita ; margo anterior 

 truncato-rotundatus, posterior magis compressus ; umbones tumi- 

 duli, apice minimo, incurvo; dens cardinalis utrinque bifidus, 

 laterales in dextra duplices, in sinistra simplices; fovea carti- 

 laginis triangularis, sinus pallialis brevis, linguiformis. — Long. 

 40 Mm. 



Mactra solida Linne ed. 12 p. 1126. — Lam. Desh. VI p. 104. — 

 Chemnitz VI T. 23, F. 230. - Forbes et Hanley I p. 351 T. 22, 

 F. 1. 5. - Sow. III. Ind. T. 3, F. 25. — Jeifreys Br. Conch. II 

 p. 415 T. 43, F. 2. — Locard Cat. p. 401. 



Trigonella gallina da Costa Br. Zool. p. 199 T. 14, F. 6. 

 Var = Mactra truncata Montagu Test. Bi'. p. 34. — Forbes et 

 Hanley I T. 23, F. 1. — Sow. III. lud. T. 3, F. 26 = crassa 



