138 PEOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



Linn., and in colour it resembles Z. pynim, Linn. The Urge aro 

 produced on the varices into short blunt spines. 



Pecten Thomasi, n.sp. PI. XI, Fig. 2. 



Testa rotundato-ovalis, tenuis, leviter inflata, aequivalvis, oblique 

 subsequilateralis, costis numerosis (circa 30) irregularibus, Icevibus 

 planulato-rotundatis instructa, estus dilute purpurascens, flavo tincta, 

 saturate pui-pureo-fusco late radiata, auriculis mediocris, insequalibus, 

 fere rectangularibus ; pagina interna saturate purpureo-fusca, ad 

 marginem maculis 5 flavis oruata. Long. 70, lat. 65 mm. 



A shell of remarkably thin substance for its size, in form and 

 character almost like one of the small hyaline species, such as P. natans, 

 Philippi, but the prevailing colour is dark. The ribs are irregular, 

 some nari-ow and close, others broader and more rlistant ; the interior 

 of the left valve is very intense purple-brown, relieved at the margin 

 by five regular, well-defined yellow blotches. 



CARDnTM Mendanaense, n.sp. PI. XI, Fig. 3. 



Testa subquadrato-ovata, gibbosa, crassa, straminea, et albida, f ulvo- 

 fusco variegata, radiatim costata ; costis 40 confertiusculis, anticis 

 rotundatis, crenatis, medianis complanatis, utrinque angulatis et 

 serratis, posticis oblique squamatis ; costarum interstitiis angustis 

 profunde excavatis, transversim rugatis ; pagina interna alba, ad 

 marginem vivide purpurea. Long. 60, lat. 50 mm. 



Hah. — Marquesas (or Mendaiia) Is. (Thomas). 



This shell, remarkable for the vivid puii:)le margin of the interior, 

 is distinguished by the number and peculiar formation of the ribs, 

 which are nearly flat at the top, and angularly spread and serrated 

 at the sides, partially overlapping the deeply excavated interstices. 



EXPLANATION OF PLATE XL 



Fig. \. Lotoriiim armatiim, n.sp. 

 ,, 2. Pecteu Thomasi, n.sp. 

 ,, 3. Cardium Meudanaense, n.sp. 



