108 NEW SPECIES OF ASTRA LIUM FROM NEW BRITAIN, 



Whorls. — Seven, inclusive of the embryonic portion of the 

 shell; the upper whorls convex, the last whorl becoming distinctly- 

 concave towards the aperture. 



Sculpture. — The first three whorls are comparatively smooth, 

 with oblique wavy lines between shoulder and suture; they are 

 angled at the shoulder by a ridge, which commences as a raised 

 thread and at about the fourth whorl breaks up into beads. As 

 growth proceeds, additional bead-lines are intercalated until they 

 reach the number of 8 or 9 rows* on the last whorl, where the 

 subsutural row is composed of large, somewhat oblique, trans- 

 versely flattened, and closely appressed beads. 



Below the subsutural row, the outer rows are placed closer 

 together, the median ones further apart. 



The imjDressed suture is sinuously wound, the spines of the 

 preceding whorl being absorbed. 



Periphery is set about in the adult with ten to twelve short 

 forwardly directed, stout, compressed spinesf of a maximum 

 length corresponding to about one-third the width of the last 

 whorl; but at the age of four Avhorls the periphery is armed with 

 11 closed tubular spines, as long as the whorl is wide. 



Base is flattened, becoming convex towards the lower lip of the 

 aperture; a double row of beads, about 50 in a row, forms the 

 margin of the spiked periphery, within which occurs a wide 

 shallow furrow, normally devoid of beads, but frequently contain- 

 ing one or even two intercalated rows; then three or, exceptionally, 

 four rows of beads encircle a heavy boss of callus, excavated at 

 the centre; proceeding from this boss a stout rib thickens the 

 anterior margin of the lip. 



Apei'ture. — Oblique, ovate, angled, and channelled at peripheiy; 

 pearly within, and reinforced at the upper angle by a heavy 



* Sometimes there is indication of a tenth row. 



t Sometimes tliere are indications of as many as 14 spines. In the adult 

 the peripheral spines may be locally quite suppressed. 



