162 C. A. Westerlund, Synopsis Mollnscorum Extramarinor. Scandin. 



riores partes altitudiiie subsequalis, marginibus parallelis, 

 fuscopicea, rufescens, forte geneo splendida, numquam ra- 

 diata, ad umbones ventricosa, infra et prascipue rostro 

 longo mediano, utrinque angustato apice subtruncato forte 

 compressa; pars antica perbrevis, humilis, postica plus 

 quam quadruplo longior, margine ventrali postice ascen- 

 dente; umbones lati, humiles, decorticati; ligamentum vali- 

 dum; dens card. crassus, elongatus, fere longitudinaiis, 

 crenatus, lamellpe crassas. Long. 110 (ant. 20, post. 85), 

 alt. 42, cr. 30 mm. 



Hah. Suecia in Ostergotland (in lacubus Follingarne *, Ki- 

 sasjon et Kilarpsjon). Forma segre interpretenda, ad tumidum 



vergens. 



**) C. postice dilatata et superne plus minus angulata, fii- 

 scovirescens, S(epe imlchre saturatius viride radiata ct 

 fuscozonata, crassiuscula, umbones sccpissime integri, 

 dens card. parvus, compressus, obliquus. 



U. balavus Mat. & Rack. (Trans Soc. Linn. 1807). C. oblongo- 

 ovalis, postice dilatata, sat ventrosa, inferne et postice 

 compressa, antice rotundata, postice 2^2 longior, in ro- 

 strum latum, linguseforme, fere medianum, subtruncatum 

 producta, margine dorsaU arcuatulo, ventrali subrecto; um- 

 bones prominuli, ventrosi; ligamentum angustum, longum. 

 Long. 60—70, alt. 30—35, cr. 20 — 25 mm. — Rossm. Icon. 

 f. 128 a. 

 Hah. Suecia in Skane (Hojea, Kopingea, Almaa &c.), Oster- 



gotland (in Stangan) et Dalarne (in lacu Hyen, par. Schildvie). 



— Dania in Sjselland (Ringstedaa &c.) et Jylland. 



Forma minor (long. 40 — 50, alt. 25 — 28 mm.), obscurior, 



subolivacea, zonis multis atrobrunneis, postice latior, subrhom- 



bea, margine dorsali magis curvato, basali subretuso, in Hojea 



et in Skenan occurrit. 



ff Umbones tuberculato-rugosi, postice margine areali infe- 

 riori {callo obtuso) obliquo utrinque ab area distincti. Dens- 

 cardinalis valvce dextrce compressus, sat crassus, longitudi- 

 nalis, posteriore valvce sinistrce valido. 



U. tumidus Retz. (Nov. test. gen. 1788). C. ovato-conica, ven- 



