SHELLS. 243 



Are very difficult to be taken from the stones enti.e. They are 

 found on stones in deep water. Bidwell. 



This species is very variable in its shape, according to the form 

 of the body to which it is attached. It is usually convex, with 

 a deep cavity beneath, but it is often quite flat above, and the sep- 

 tum is raised above the margin of the cavity beneath ; and lastly, 

 the two ends of the shell are often bent towards each other below. 

 The ribs are almost always present, as is also the dark colour, but 

 sometimes the shell is quite white. 



111. Crepidula contorta. Quoy et Gaim., Voy. Astrol., 

 iii. 418, t. 72, f. 15, 16. 



Inhabits Bay of Islands. 



Always white and smooth ; differs greatly in external form and 

 the depth of the cavity. 



112. Calyptrcea dilatata. Sow., Gen., f. . Cre- 

 pidula maculata. Quoy et Gaim., Voy. Astrol., iii., 

 422, t. 72, f. 6-9. 



Inhabits New Zealand. Yate. Bay of Islands. Dief- 



fenbach. Great Barrier Island. Dr. Sinclair. 

 The normal form of the shell is to have a round outline beneath, 

 but in the smaller specimens, which have grown in a confined 

 space, the front of the aperture is often produced, and the right 

 side so contracted that the shell assumes an elongated shape like 

 a Crepidula, from which it is chiefly to be distinguished by a small 

 cavity on the axis, near the angle of the inner lip, and its more 

 acute spire. 



Fani. BULLION. 



113. Eulla Quoyii. Gray, n. s. Bulla striata. Quoy et 

 Gaim., Voy. Astrol., ii., 354, t. 26, f. 8, 9. 



Inhabits New Zealand. Quoy. Stanger. 

 Shell ovate, smooth, marbled with purplish-grey and white dots ; 

 spire perforated. 



Like Bulla striata, Lam , but quite distinct. 



114. Bulla Australis. Gray. King's Voy. N. H. Quoy et 

 Gaim., t. 26, f. 38, 39. 



Inhabits New Zealand. Yate. 



115. Bulla Zelandice. Gray, n. s. 

 Inhabits New Zealand. Dr. Dieffenbach. 



Shell ovate, subglobose, imperforated, thin, pellucid, very slightly 



R 2 



