122 
and has a very different sculpture and pallial sus. The concentric 
strize are a little broader than the interstices, elevated, but of an un- 
equal height, not diminishing much towards the sides, and there be- 
coming lamellar. The pallial sinus is not widely open, is extended to 
the middle of the shell, and included by lines which are a little con- 
cave and form a small round vertex. The latter is marked with a 
pale rust-coloured stain, which is produced upwards, and disappears 
by degrees. 
8. Dosinra SALEBROSA, Romer. D. testa oblique quadrangulari 
rotundata, vir altiore quam longa, antice posticeque obtuse et ro- 
tundatim truncata et biangulata, tumida, valde inequilaterali ; 
lamellulis transversis, densis, tenuibus, irregularibus, ad extre- 
mitates in foliis sparsis, erectis conversis ; calcarea, opaca; um- 
bonibus tumidiusculis, prominentibus, recurvis, in + longitudinis 
sitis; margine ventrali postice dependente, medio subcurvato, 
antice fere perpendiculariter, postice oblique adscendente ; margine 
dorsali antico brevi, vix concavo, postico valde descendente, longe 
curvato; lunula triangulari-cordata, impressa, circumscripta, ~ 
longitudinaliter striata, foliis brevissimis circumdata ; area an- 
guste lanceolata, valde excavata, foliis parvis cincta; ligamento 
valde immerso, vix conspicuo ; intus alba; sinu palliari mediocri, 
late aperto, in apice rotundato, lineis includentibus subrectis, 
superiore subhorizontali ; dente laterali mediocri, papilliformi, 
secundo cardinali in valva sinistra crasso, tertio in dextra lato, 
producto, profunde inciso. 
Long. 22°5, alt. 23°5, crass. 13 mill. 
Hab. Malacca. 
In the outline this shell much resembles D. lucinoides of Reeve, 
but by the sculpture and size can be readily distinguished from it. 
In consequence of the straightness of the basal margin, and the 
rounded truncation of the sides, there are produced four obtuse angles 
on the margins, whilst the posterior part of the basal margin projects 
a little downwards. All the surface is covered with fine, close-set, 
slightly elevated lamellze, running irregularly and growing elevated 
and leaf-like at the sides, particularly on the hinder part, so as to ter- 
minate the ligament-area with a wreath of short leaf-work. The 
pallial sinus is distinguished by its wide opening, and by its broadly 
rounded apex. The exterior of this shell is calcareous, without any 
lustre. 
9. Dostn1tA TRIPLA, Romer. JD. testa rotundato-triangulari, sub- 
inequilaterali, inflata, tenui, vix longiore quam alta; striis trans- 
versalibus, subrotundatis, vie elevatis, interstitiis equantibus, sub- 
regularibus, ad latera tenuibus, non elevatioribus cincta ; albida ; 
umbonibus acutiusculis, maxime prominulis, incurvis, in 2 longi- 
tudinis positis ; margine ventrali subcurvato, ad latera vix adscen-. 
dente ; margine dorsali antice oblique et subrecte descendente, 
postice obliquo, subcurvato, in utroque latere fere usque ad basin 
producto ; lunula maxima, totam declivitatem anticam occupante, 
