THRACIA.— Plate II. 



dec-lares that the Portland specimen, the traditional type of 

 that shell, was similar to it." But not having faith in 

 Montagu's judgment, they expunge Pennant's name and 

 adopt the next in priority, of the correct application of 

 which no doubt exists, pnbescens of Pulteney. There ap- 

 pears to me strong reason for believing that Pennant's 

 M>/a declivis was not a Thracia at all. Speaking of its 

 habitat, he says, " It is common among the Hebrides, by 

 the gentry of which islands its animal is eaten." With Mya 

 arenaria, of which Pennant's shell was probably a small 

 specimen, this is the case, but Thracia pubescens is only 

 found at the extreme south-west of England, on the shores 

 of Devon and Cornwall. 



Species 11. (Mus. Cuming.) 



Thracia magnifica. Thr. testa oblongo-ovatd, tenui- 

 culd, parum comsexd, postice Jlexuoso-angalatd, ant ice 

 rotundatd, subpellucido-albd, valide granoso-scabrosd 

 ct concenirice elevalo-striatd, oblique ampliter corru- 

 gato-plicald, plicis margine antico oblique descenden- 

 tibus, in valrd di'xtrd fortioribus. 



The magnificent Thracia. Shell oblong-ovate, rather 

 thin, but little convex, posteriorly flexuously angled, 

 anteriorly rounded, semitransparent-white, strongly 

 granosely scabrous and concentrically excavately stri- 

 ated, obliquely largely wrinkle-plaited, plaits ob- 

 liquely descending from the anterior margin, stronger 

 in the right valve. 



Jonas, Mollusken Beitriige. 



llab. Honduras; Dyson. 



The interesting shell figured in the accompanying Plate 

 was procured by Mr. Cuming from the late Dr. Jonas, of 

 Hamburg, who described and figured it with the above 

 name in his ' Mollusken Beitriige.' Nothing was known of 

 its habitat, but it happened shortly afterwards that an odd 

 valve of the same species came into Mr. Cuming's posses- 

 sion among some shells collected by Mr. Dyson at Hon- 

 duras ; and, though resembling in typical character T. 

 granulosa of the China Sea, it was found to have both a 

 typical and local relationship with T. plicala of California 

 and the West Indies. There is a broken valve of the spe- 

 cies in the British Museum, labelled, on what authority I 

 know not, Thracia semimgosa. 



