tun i i . \ i \< i N \. 



lire. that mi the periph. i m<l diipli 



nearly sumo tli band within tin- peripheral lira-, I hen wil I, 

 .rramilar line round the umbilici^. |)iain. 1 * mill. 



/,' 



II. v< I.OSTOMA, and K. CIKM in. BoUTg, linfigUl 



A'///' T'l II /!> 



Genus LACUNA, Tnrton, L 



Sect i., n LACUS \ < sensu -tricto.) 



L. rrn:<i.r>, Tin-ton. IM. ;">(), fi--s. .">!, .VJ. 



BemiglobOBO) slightly cxpandt-d at tin- la-c. |M-ri|)licrv .lin 

 aiiLriilatcd, rather Bolid, opaque, gloasy ; whitish, yrllowish or n-ddi-h 

 whito, sometimes trifasciate, t he middle l.an<l lro:nlest ; 

 narrow, deep. Length, 4 mill. 



Northern E'U i- <>!>,. /'//////. 



//. auricularis, Mont,, L.fasriata, J. Adam-, /,. /rrr<t, l> 

 //r//> litrnim, Mont., />. nt/a, Dorset, ('atal., /,. Mnnl-njni, Tiirton. 

 //. expansa, J. Adams, />. pallidula, Meyer & Mohins, />. /'//// ///- 

 Locard, are all synonyms, besides the <|iiasi-vai-ietal names 00 

 ladea, clausa, expansa, etc., of Jeffreys. 



L. PALLIWLA, DaCosta. PI. 50, %s. ">:{, .l.'ia. h. r>4. 



Widely umhilicated, larircly, ohliqiicly ex])anded, rathei- thin. 



Opaque, glossy ; under the epidermis are L r n>wth lines and a 



spiral scratches ; pale yellowish or olivaceous yellow; \vln>rl> :; . J. 



rapidly increasing, the last dis;)rop<irtinately lar-v, sutun- deeply 



ini|)ressed. Diam. -i) mill. 



Nort/imi Europe, Iceland, Gre< ,,!,, <1, >)</'/:/>//;/ 



/,. nrrifoitlrn, Gould (fi.ir. ")4 i, I.. /nitn/ii, Thorpe. L. I 



I'hil., and vars. 9ubtriangulari8 t Kohdt, and <///// *<> //>. Th. 



synonyms. 



L. I'OKKI.CTA, Carpenter. IM. .">(>. i\<^. 56, 56, 



Larger than />. />t(f>/u.^ with more developed spire. lody \\horl 

 slopin-'Iy expanded, efl'use helow, thinly >|irally -triatr upmi tin- 

 thin olivaceous yellow or liirht hrown cpidermi>. -nmetiiiH- witli a 

 pale hand tinder the obtusely aniriilated periphery. 



Length. !."> mill. 



1"" 



