THE NAUTILUS. 



57 



which is opaque white and smooth. Subsequent whorls are flattened 

 but separated by a deep suture, the earlier ones having two spiral 

 beaded cords. At the end of the first 3^ to 4 whorls a third spiral 

 cord appears. The last whorl is rounded periferallj, and has about 

 10 spiral cords, separated by spaces of about their own width ; the 

 upper 5 or 6 are nodose at the intersections of low, narrow, vertical 

 folds, which do not extend below the perifery. The last whorl has 

 a low, rounded, rather massive varix behind the outer lip. Aperture 

 oval, produced in a short, deep channel at the base. 



Length 3.34, diam. 1.39 mm.; whorls 6^. 



Hilo, Hawaii. Types no. 95906 A. N. S. P., collected by Mr. 

 D. Thaanum. 



This tiny Bittium is somewhat related to B. leucocephaJum Wat- 



-€ 



,^- 



Fig. 1. 



Fig. 2. 



Fig. 3. 



son, described from the reef at Honolulu, from which it differs in 

 many details of shape and sculpture. Watson's type is evidently an 

 immature shell, smaller than B. ht'loense, but it has 8 whorls, while 



hiloense has but 6^. 



Torinia discoidea sterkii n. subsp. Fig. 2. 



The shell is depressed, biconvex with flat perifery, widely umbili- 

 cate, the width of umbilicus contained 2.6 times in that of the shell. 



