409 
Var. 5. ROSEA. 
Color saturate roseus, apice teste albescente, umbilico pervio. 
Long. 15 cm., diam. apert. 6 mm. 
Hab. Zauzibar (coll. Cuming. ). 
A specimen in the collection of Chr. VIII., which I suppose is the 
original specimen of Chemnitz, although it is somewhat smaller than 
the figure (Diam. maj. 11 mm., min. 10 mm., diam. apert. 4 mm.), 
offers no important difference from the specimens of S. senegalensis, 
Récluz. The var. é is of a bright rose-colour; but I cannot regard 
this circumstance as of specific value, although the locality indicated 
is very different. Var. 6, with a pale yellow-red apex, shows a trans- 
ition in colour. 
11. Tenaconus (Siz1quaRius) PONDEROsUuS, Morch. 
T. crassa ponderosa candida trochleatim contorta, umbilico pervio 
latiusculo ; anfr. 3} (primi desunt) compressiusculi, obtuse an- 
gulati, superne planati, radiatim leviter sulcati, spiraliter le- 
viter undulato-striati unde decussati, transversim profunde et 
conferte fissurati et striati; anfractus ultimus longus rectus 
subdeclivis, inferne grosse liratus, stratis crassis irregularibus 
circiter 8 compositus. Rima canaliculata simplex, margine 
superiore leviter undulato, aperturam versus angulata, in anfr. 
primis clausa vel omnino obliterata. 
Long. 44 cm., diam. anfr. ult. 20 m., diam. ap. 10 m. 
Operculum ut id 8. australis, var. 3, sed ciliis longioribus, anfr. 
num. 7-8. Diam. 8 mm., alt. 5 mm. 
Hab. Port Essington, 7 fathoms, sandy mud (Jukes) ; col. 
Cuming. A single specimen, attacked by a burrowing Annelide. 
This is one of the newest and largest Univalves. 
Subgenus Pyxreoma, Morch. (véis et ropa.) 
Rima hians marginibus utringue acutis, postice lamina interna 
clausa sed non repleta. Operculum spirale, margine ciliato, 
axis dissepimentis simplicibus. 
12. Tenacopus (Pyxrpoma) Lacteus, Lam. 
T. gracilis nitidiuscula, pellucens, alba, obsolete fuscescens, longitu- 
dinaliter limbata, liris inferne prominentioribus, spiram versus 
evanescentibus ; striis incrementi expressis et reflexis, juxta 
rimam obsoletissime fissuratis. Testa infantilis castanea am- 
pullariformis. Rima hians utrinque acutissima. 
Long. 13 cm., diam. ap. 3 mm. 
Operculum subcylindricum, gyris circiter 18 confertissimis, ciliis 
marginalibus validis ; axis polythalamius superne mammillatim 
prominens; area levigata profunde immersa, peripheria exca- 
vata; lamina marginalis convexa, nitida flavescens, linea im- 
pressa peripherica notata. 
Diam. 2 mm., alt. 21 mm. 
