yOLDIA.— Plate III. 



Thk arctic You)ia. Shell compressed, oblong- 

 liinceolato, shining, olivaceous, concentrically 

 striped with brown ; posterior side a little atte- 

 nuated, dorsal margin depressed, area a little 

 convex, defined, ventral margin suddenly sloped 

 upwards, end truncated ; anterior side sinuated at 

 the ventral margin; lunulo convex, scarcely 

 defined. 



Quay. (Nucula) Parry's Voyage, Appendix, p. 2-1]. 



Nucula eascoensis, Migha;ls. 



Nucula Myalis, Hanley. 



Yoldia Hyperhorea, Tor.-ll. 



Hiib. Spitzbergen. 



Siiccies 1.'). (Mus. .' copied.) 



Yoldia obe.sa. Yot. testd ventricosd, lata, snbovatd, 



kvvigatd ; latere postico majuscido, late truncato ; 



margiite ventrali levitcr cnnrexo : latere antica 



breriusculo, rotundv. 

 The oiiEsi: Yoldia. Shell veutricose, broad, subovate, 



smooth ; jx)sterior side rather the larger, widely 



truncated ; ventral margin slightly convex ; 



anterior side rather short, rounded. 

 Stimpson. Shells of New England. 

 Hah. North America. 



I do not observe any specimen of this in the Britisli 

 Museum. 



