56 



T. rotundata, leevi, sub-compressa, utrinque valde hiante ; 

 auriculis aequalibus, obtusis, parvis ; interne costis 22, dupli- 

 catis, vel 44 singulis ; colore valvee sinistree rubro, gviseo, 

 radiatim fasciato, fusco-rubescente concentrice fasciato, prope 

 umbonem lineato ; valvee dextree albo. Long. 5.; lat. 1. 20.; 

 alt. 5. 20.; poll. 



Differing from P. Plenronectes in having twice the num1)er 

 of internal ribs^ in being rather rounder, and more gaping. 

 The colour of the upper valve is dull red, with concentric 

 lines and bands of a darker tint, with faint light rays. 



China and Japan. 



32. P. Laurentii. (pi. xvi. f. 137, 138.) GmeL p. 3317- 



T. sub-rotundata, ad latera sub-angulata, laevi ; auriculis latis, 

 rectangulatis, marginibus undulatis ; valva sinistra sub-com- 

 planata, lateribus elevatis, costis internis 47 ; valva dextra 

 ventricosa, ad latera subcompressa, costis internis 41 : colore 

 valvte superiorioris rubro-fuscescente, puUide fulvo-radiato, 

 albo-raaculato ; valvse inferioris pallide fulvo, fusco-radiato, 

 umbone albo. Long. 3. 40.; lat. 0. 75.; alt. 3. 25.; poll. 



Rather rounded, with a rounded angle at each side, smooth ; 

 with wide straight auricles, slightly undulated at the margins ; 

 the upper valve rather flattened in the centre, and elevated at 

 the sides, the lower valve correspondingly ventricose in 

 the centre; there are about 47 internal ribs ; the colour of the 

 upper valve is of a reddish brown, faintly radiated with darker 

 brown, speckled with white ; the lower valve has a shade of 

 pale fawn, from the centre to the margins, radiated with pale 

 brown. China. 



33. P. Magellanicus. (phxvi. f. 122.) GmeLp.3317. 

 No. 9. 



T. rotundata, sub-compressa, utrinque hiante, striis nume- 

 rosis scabris minutis radiata ; auriculis striatis, latis, rectangu- 

 latis; valva sinistra quam altera magis ventricosa; colore valvee 

 sinistree fusco ; valvee dextrse pallide fulvo. Long. 3. 80. ,- lat. 

 0. 90, ; alt. 3. 80. ; poll. 



Rounded, rather flat, gaping at both sides, radiated with 

 numerous rough minute striee ; the auricles striated, wide, 

 rectangular ; the upper valve more ventricose than the lower ; 

 the colour of the upper valve is brown, that of the lower 

 nearly white. This species, notwithstanding its name, does 

 not come from Magellan but from Massachusets. 



34. P. PsEUDAMrsiUM. (pL xix. f. 211. 212. and pi. 

 XX. f. 243.) Klein. Moth. Ost. 146. p. 134. 1. 9. f. 31. P. 



