20O 



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

 latis,confertissimis, tenuibus,fulvis : long.1'9, alt. 1-5, lat.0'65 poll. 

 Hah. ad Sanctam Elenam. 



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

 at St. Elena.— G. B. S. 



Amphiuesma punctatum. Amph. tesid ovali, crassiusculd, alhi- 

 cante, sparsivi roseo fulvogue maculatd : postice subtruncatd, plied 

 Jlexuosd posticali distinctd; disco externo concentrice impresso- 

 punctato; marginihiiSyinferiori costis nonnulUs concentricis latis, 

 dorsalibus nntice et postice roseo maculatis ; long. 1'7, alt. I "35, 

 lat. 06 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, Icevigatd, 

 tenuissime radiatim striatd; parte mediand anticdque striis elevatis, 

 subconcentricis, Jlexuosis decussatd ; margine posticd subjiexuosd ; 

 epidermide tenuissimd,Jlavescente: long. 87, alt. 0'8, 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. testd ellipticd, albd, subobligud, 

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

 breviore, oblique subtrwicato ; superjicie concentrice leviter striatd : 

 long. 2, alt. I-?, 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 ; intus Jlavescente : long. 2'], 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 p)alHde roseis nonnunquam pictd, concentric^ ru- 

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

 Hab. in littoribus Novae 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 Ion. 

 giludinalibus, minutis, crcberrimis, fused luteo maculatd, maculis 

 numerosissimis ; labro dilatato, latissimo, spiram longi praster- 

 eunte ; labio crenulato, sublutco; long, li, lat. \\ poll. 



