200 



sali posticd rcctiusculd crenulatd; costis concentricis, acutis, crenu- 

 latis, confer tissimis, tenuibus,fulvis; long.1'9, alt.lb, lat.0'65 poll. 



Hab. ad Sanctam Elenam. 



A single valve of this elegant species was picked up on the sands 

 at St. Elena.— G. B. S. 



Amphidesma punctatum. Amph. tesid ovali, crassiusculd, albi- 

 cante, sparsim roseo fulvoque maculatd ; postice subtruncatd, plied 

 Jlexuosd posticali distinctd; disco externo concentrice impresso- 

 punctato; marginibuSy inferiori costis nonnullis concentricis latis, 

 dorsalibus antice et postice roseo maculatis ; long. 1*7, all. 1*35, 

 lat. 0*6 poll. 



Hab. ad Insulas Gallapagos. 



A perfect specimen and a single valve are all that Mr. Cuming 

 obtained. — G. B. S. 



Amphidesma lenticulare. Amph. testa albd, lenticulari, l&vigatd, 

 tenuissime radiatim striatd; parte mediand antiedque striis elevatis, 

 subconcentricis,Jlexuosis decussatd ; margine posticd subflexuosd ; 

 epidermide tenuissimd,Jlavescente : long. 87, alt. OS, lat, 4*5 

 poll. 



Hab. ad Sanctam Elenam. 



A single specimen was dredged from a depth of six fathoms in 

 sandy mud. — G. B. S. 



Amphidesma ellipticum.— Amph. testdellipticd,albd,subobliqud, 

 kevi, epidermide fused ; latere antico longiore, rotundato, postico 

 breviore, oblique subtruncato; superjicie concentrice leviter striatd .• 

 long. 2, alt. \-7 , lat. 075 poll. 



Hab. in Columbia Occidentali (Monte Christe). 



Inside pure white. Dredged at a depth of nine fathoms in sandy 

 mud.— -G. B. S. 



Amphidesma corrugatum. Amph. testd suborbiculari, albicante, 

 radiatim striatd, concentrice rugulosd ; epidermide fused ; margine 

 dorsali posticd recta, inclinatd ; intusjlavescente : long. 2*1, alt. 

 1-9, lat. 1 poll. 



Hab. in Peruvia et ad Iquiqui. 



Dredged from coarse gravel in ten fathoms water. — G. B. S. 



Amphidesma australe. Amph. testd suborbiculari, rotundatd, 

 albicante, radiis pallide roseis nonnunquam pictd, concentrice ru- 

 gosd : long. \, alt. \, lat. 0*5 poll. 

 Hab. in littoribus Novse Hollandiae et ad insulas Oceani Pacifici. 

 Found by Mr. Cuming in the crevices of the coral rocks at Lord 

 Hood's Island. 



I have had the printed descriptions of the three last species by me 

 for several years, but they have never been published. — G. B. S. 

 Genus Neritina. 

 Neritina latissima. Ner. testd rotundatd, ventricosd, striis lon- 

 gitudinalibus, minutis, creberrimis, fused luteo maculatd, maculis 

 numerosissimis ; labro dilatato, latissimo, spirant longe prater- 

 eunte; labio crenulato, subluteo: long. II, lat. \+ poll. 



