4 
41 
Shell rather solid, subopake, smooth, strongly concentrically 
wrinkled, longitudinally obsoletely substriated ; posterior side acu- 
minated, subtruncated; dorsal margin posteriorly sloping ; spoon- 
shaped process thick and wide ; ventral margin strongly arcuated. 
Hab. Ceylon, on the sands. (Mus. Cuming.) 
ANATINELLA DILATATA, Adams. A. testd ‘tenui, fragili, concen- 
tricé corrugatd, longitudinaliter striatd, latere postico dilatato, 
oblique valde truncato, margine dorsali postice horizontal recto, 
processu cochleariformi parvo tenut, dentibus cardinalibus valdé 
divergentibus ; margine ventrali arcuato. 
Hab. ? 
Shell thin, fragile, concentrically wrinkled, longitudinally striated ; 
posterior side dilated, obliquely strongly truncated; dorsal margin 
posteriorly horizontal and straight ; spoonshaped process small, thin ; 
cardinal teeth greatly diverging, ventral margin arcuated. 
Hab. Puteao, Philippines, on sand-banks, at low water; H. C. 
(Mus. Cuming.) 
ANATINELLA vENTRICOSA, Adams. A. testd tenut, ventricosd, 
semipellucidd, concentricé corrugatd, longitudinaliter conspicue 
striatd, striis elevatiusculis, latere postico rotundato ; margine 
dorsali postice declhivi ; processu cochleariformi tenui, angusto ; 
margine ventrali leviter arcuato. 
Hab. ? 
Shell thin, ventricose, semipellucid, concentrically wrinkled, lon- 
gitudinally conspicuously striated, strie rather elevated, posterior 
side rounded, dorsal margin posteriorly sloping ; spoonshaped process 
thin, narrow, ventral margin slightly arcuated. 
Hab. Puteao, Philippines, on sand-banks, at low water ; H.C. 
(Mus. Cuming.) 
February 26, 1850. 
W. Spence, Esq., F.R.S., in the Chair. 
The following paper was read :-— 
1. Monocrapus or CycLostREMA, MaRRYAT, AND SEPARATISTA, 
GRAY; TWO GENERA OF GASTEROPODOUS Moutuusks. By 
Artuur Apams, R.N., F.L.S. etc. 
CycLosTREeMA, Marryat. 
Animal ignotum. Operculum 
umbilicata ; apertura circularis. 
Shell depressed ; aperture circular ; umbilicus very large, with the 
volutions of the whorls visible within it. 
? Testa depressa, perspectivo- 
CycLoOsTREMA CANCELLATA, Marryat. C. testd albd, lineis lon- 
gitudinalibus et transversis elevatis decussantibus inde cancel- 
