LAMINELLA, OAHU. 331 



Fig. 5 is from a Wahiawa shell, fig. 4 from a slightly older 

 Ahonui shell, plate 56. 



The embryonic whorls but slightly convex with non-im- 

 pressed sutures, and very finely striate, reminding one 

 forcibly of Amastra turritella, some forms of which have 

 much the same contour. The last 3 or 4 whorls have, on a red 

 ground, angular, zigzag, black streaks, sometimes separate, 

 sometimes enmeshed, forming varied patterns, as shown in 

 the figures. The outlines of the spire are always concave. 

 The columellar lamella is strong and enters subhorizontally. 



'In adult shells the protoconch and part of first volution 

 are dark and have a glassy, smooth aspect. This changes 

 on the second and third whorls to opaque purple or ashen, 

 and fine striae of growth appear. Dark blotches or longitu- 

 dinal bars appear in many shells before this, even on the 

 second or third volution, but these are straight, coincide with 

 the growth-bands of the shells, and are often discontinued on 

 the latter part of third or first part of fourth volution. These 

 must, however, be reckoned as the forerunners of the zigzag 

 pattern of the later stage, because in some shells they are not 

 discontinued but pass into the zigzag lines of the fourth volu- 

 tion, and in some examples a zigzag form is assumed by iso- 

 lated bars in the midst of the straight ones. A faint pink 

 hue comes in usually on the latter part of the fourth volu- 

 tion, and at about the same time the black zigzag markings 

 of the later stages begin to make their appearance with regu- 

 larity. The color deepens into a pinkish red on the sixth 

 volution, and the zigzag markings become broader ; on the 

 seventh volution the zigzags usually enmesh, and near the 

 aperture, in old shells, form a black periostracum. The aper- 

 ture is usually deep pink with a dark border ; columella simi x 

 lar with a white subhorizontally entering tooth and dark re- 

 flected umbilical margin. 



"In a living condition this shell is covered by a vegetable 

 growth, apparently an alga, that entirely covers the shell 

 except where worn off or kept away by friction in front of 

 the aperture. No part of the elaborate pattern and brilliant 

 color therefore is visible in the living animal. Each apical 



