iV<?tt' species of Aviasira. 13 



gr.idaally far within the margin. Umbilicus rather small, semi- 

 circular in cross section. 



Length 13. i, diam. 7.4, apert. 6.0 mm.; 6] i whls. (Holotype) 

 13.4, " 7.8, •• 6.3 " 6^4 " 

 " II-3. " 6.2, " 5.1 " 6 " 

 1 1. 2, " 7.0, " 5.0 " 6% " 



Kauai: Pleistocene deposits ofHanamaulu plains south of 

 Wailua river (Dole and Cooke). 



Holotype and cotypes No. 41,998, paratypes No. 19,476, 

 Bishop Museum. 



This extremely variable form is abundant in road cuttings on 

 the coastal plain south of the Wailua river. There are several 

 distinct forms found associated in the different deposits. The 

 typical form described above might be considered a distinct species 

 if it did not occur with numerous intergrades of other form which 

 closeh- approach A. rugulosa yiormalis. A constant differentiating 

 character between all these specimens of annosa and norvialis is 

 the verj- weak, oblique, deeply situated columellar fold of the 

 former. Some of the specimens of annosa at first glance seem to 

 belong to the subgenus Cyclamastra but the embryonic whorls are 

 less convex than those of any species of this subgenus. 



All the specimens of this variety are openly perforate except 

 those of a rather rare narrow form. The third series of measure- 

 ments given above is taken from one of the narrow imperforate 

 examples ; the first and second series of measurements are of 

 typical examples ; while the last is from a specimen which in 

 form and position of the aperture closeh- approaches normalis. 

 In the tj-pical form the aperture is slightly diagonal and contracted 

 above. 



( Pla vescen s Series . ) 

 A. flavescens var, emortua, n. var. 



I'l. A. FiK. 6. 



The shell is imperforate, conic, solid. In its fossil state of a 

 very light vinaceous color, the surface nearl\- smooth, iudistinctly 

 and irregularly sculptured with growth-striae. The spire is elong- 

 ate-conic, with slightly convex outlines. The embryonic whorls 



(23'] 



