80 AURICULELLA, OAHU. 



iety predominates in each colony, and a few of the color- 

 varieties are limited to single colonies. Most of the color- 

 varieties are found in nearly all the colonies, though occa- 

 sionally one or more are absent. The colonies from the western 

 side of Nuuanu have sometimes a small tubercle at the junc- 

 tion of the outer lip, but this character is entirely absent in 

 the shells from the eastern side and also the Pauoa shells. 



The most common color-varieties are: (a) brown with a 

 slightly darker spire ; (&) unicolorous brown ; (c) light brown 

 striped with a darker shade ; ( d ) brown with a narrow 

 white baud at the periphery; (e) brown with a very broad 

 whitish band; (/) chestnut with a narrow white band bor- 

 dered above and below by two narrow dark brown bauds; 

 (g) yellowish white with a very narrow brownish band; (h) 

 brownish with a broad dark brown band; (i) light brown 

 with a narrow dark brown band and slightly different shades 

 of yellow. The lip is dark brown, light purplish brown or 

 white. 



A. pulchra and A. montana are closely related to A. auri- 

 cula, and there are colonies which seem to contain both auri- 

 cula and pulchra as well as some specimens which are difficult 

 to decide upon. Yet throughout nearly all of the range of 

 pulchra (from the western Nuuanu ridge westward, on the 

 southern slopes of the range) there are no true auricula 

 whatever. 



The undescribed form named A. pellucida by Gulick (Evo- 

 lution, Racial and Habitudinal, p. 220, 1905) is straw yellow 

 (varying to naphthaline yellow) with white sutural line, the 

 spire paler or cinnamon, or rarely the whole shell is cinna- 

 mon. Most of the specimens have no callous in the posterior 

 angle of the aperture, but when present it is very small. The 

 expanded lip is not thickened or ' ' duplicate ' ' ; length about 

 7 mm. This form has the characters of A. auricula (and in 

 fact can be exactly matched in Palolo auricula), but it is in 

 the territory of A. pulchra. It comes from Kaliuwaa (pi. 

 24, fig. 10), Punaluu and Hauula (Gulick coll. in A. N. S. P., 

 no. 92503, etc., and in Bishop Mus.). 



Length 7.8, oblique diameter 4 mm. 



