Y C) L I) 1 A. 



IV 



(Mus. Tc 



copied.) 



Yui-DIA FiiiGiDA. Yol. testa breviter ovato-suhrotiiniU'i, 

 minulA, tenul, stramined, nitidd, concent rice striald : 

 latere postico angvlato, post angidum late truncato, 

 inargine dorsali brevisdmo, cuneato, convexe S7ib- 

 arcuato ; unibonibus elevatis, mari/iTie ventrali semi- 

 lunari : latere anltco subrotiintlo, margine dorsali 

 declivi. 



Thk kiiigid Ynr.DiA. Slicll shorllv r:itlicr riiumleil 

 ovate, minute, thin, straw-coloured, sliiiiiiig, con- 

 centrically striated ; posterior side angular, widely 

 truncate behind tlie angle, dorsal margin very 

 short, cuneate, convexly slightly arched ; uniboes 

 elevated, ventral margin semilunar ; anterior side 

 somewhat rotmded, dorsal margin sloped. 



ToRELi.. Spitzbergen Molhisca. ].. ] ix, ]>1. i. i. :'>. 



Hah. Spitzbergen. 



This little shell is the most orbiculiw in f'ni-ni i>(' 



all the species. 



SjK'cies 17. (Mus Hrit.) 



YoLDi.v LUCIDA. Yol. tcstd parvd , oratd, len.ui, Icevi- 

 ijatd, subuentrlcosd, subcequilaterali, semipellucidd, 

 pallide stramined, slrigis concentricis cteruleis fas- 

 ciatd ; latere postico subacurninato. ared (hirsali 

 depressd, viv definitd : latere anlico subrotiindo, 

 margine dorscdi declivi. 



The hx-id Yoldia. Shell small, ovate, thin, smootli, 

 subventricose, subequilateral, seniipellucid, pale 

 straw, banded with concentric bluish stripes: 

 posterior side slightly acuminated, dors<il area 

 depressed, very little defined ; anterior side some- 

 what roimded, dorsal margin sloped, 



LovEN. Index Moll. Scandinav., p, 34. 



Hob. North Europe. 



Species is. (Mus. Brit.) 

 YoLiiiA SAi'OTii.i.A. Yol. testd ovatd, laid, coinpre 

 nitenti. oliniced, Murqiw; ffiitrali seiniluiin 



latere postico breviiisculo, swmm subcrcuato, acu- 

 miiutlo, margine dorsali depresso, ared definitd, 



TllK SOAPY Y'OLDIA. Shell ovate, broad, compressed- 

 shining, olive, ventral margin semilunar ; posterior 

 side rather short, slightly arched upwards, acumi- 

 nated, dorsal margin depressed, area defined. 



(ioL'Lli, Invertebrata of Massachusetts, )>. KKI. I'. (11. 



Hob. Massiichusetts. 



es i- Yoldia ar<:tic„, 



Tlic nearest ally of thi 



aeeper, anc 



the ventral margi 



rularlv 



Species 111. (Fig. a. b, .\Ius. Brit.) 



Yni.iuA cyc;.m.i;a. Yol. testd parvd, teuui, rentnconis- 

 si/ad, oiivaceo- fused, Icevigatd ; latere postico siib- 

 atlcHuato, ad terminum rotundato : uiid)onibus 

 rotiiiidatis. elevatis, margine ventrali coiivexo : 

 lali-re aiitico breviii>tcuIo, margine dorsali declivi. 



Tmk PViniY Y.pi.i.iA. Shell small, thin, very venfricosc. 



attenuated, rounded at the end: uml.ocs rounded, 

 elevated, ventral margin convex : anterior <idi- 

 rather short, dor.sal margin slojied. 



Mi-xsTEi!. (Nucula) Philijipi Moll. Sic. (fo.ssil.) 



La-da lenticulus, Muller. 



Lceda tenuis, Jeffreys. 



Hab. Britain. N. Europe. 



This minute shell is mori' ventricose, and has larger 



umboes than Yoldia lucida. 



Species 20. (Fig. a, h. Mus. Brit.) 



Yoi.iiiA Japoxica. Yol. testd oblongd, subarcuatd, pal- 

 lidd. la-vigatd : latere postico angustiori, supernr 

 ubfri.sr'iicumiiiato, margine ventrali subito sursitm 

 (i,r/,rl. Ni'irt/iiif- dor.'iali depresso, ared impressd 

 d'-p'iiit'i : liilrri' antico stdjrotundo, margine dor.inii 

 declivi. 



