212. Arca (Macrodon) Dalli Smith, 
Testa transversa, oblonga, valde iraequilateralis, antice rotundata, postice obliquiter 
arcuatim truncata, ad extremitatem acute rotundata, sordide albida, epidermide fusco- 
olivacea concentrice lamellata induta. Valvae mediocriter tenues, undique tenuiter liratae, 
inerementique lineis sculptae. Pagina interna caeruleo-albida, nitida, tenuiter radiatim 
striata, margine externo vix erenulato. Area ligamenti angustissima, linearis. Linea car- 
dinalis dentibus paueis (eirciter 8—10) inaequalibus antieis, duobusque posticis perelon- 
gatis, margine dorsali parallelis, instrueta. — Smith. — 
Long. 31, alt. 18, crass. 12 Mm. 
Area (Macrodon) Dalli Smith Report Challenger Lamellibranchiata p. 269 
pleigehe 20. 
Aufenthalt in den japanischen Gewässern. 
213, Arca (Macrodon) sagrinata Dall. 
„It has a hinge much like that of M. asperula Dall, but its external surface is enti- 
rely different; there are numerous concentrie grooves, with wider interspaces covered 
everywhere with an oblique chagreened orpamentation; beside this there are obsolete 
radiating series of minute scales, probably stronger in some speeimens, and on and behind 
the ridee from the umbo to the posterior angle of the margin are four well defined and 
two or three obsolete nodulous radii. The valve is about 6 mm. long and quite inflated; 
the umbones must nearly touch in perfect specimens, as the area is extremely narrow 
and the beaks well developed“. — Dall. 
Macrodon sagrinata Dall Rep. Blake Bivalvia p. 245. 
Nur eine einzelne Schale in den cubanischen Gewässern 1885 vom Albatross 
in 80 Faden Tiefe gedrakt. 
