78 HALIOTIS. 



Group of H. excavata. 



Shell subcircular, very convex, spire subcentral ; spirally lirate 

 and radiately folded. 



Australia. 



Section Padollus Montf. 



Group of H. parva. 



Upper surface closely spirally striated, having a strong, rounded 

 spiral rib inside the row of holes ; with or without radiating lam- 

 ellse between that rib and the spire. 



Group of H. pulcherrima. 



Small ; upper surface radiately corrugated, scarcely striated 

 spirally ; 7 to 8 holes open. 



Group of H. ovina. 



Spiral striation obsolete ; having coarse radiating folds above, or 

 a spiral row of tubercles ; no spiral rib inside the row of holes ; per- 

 forations 4 to 5. 



Group of H. brazieri. 



Flattened, with a spiral rib inside the row of holes ; surface 

 smooth, without radiating folds or spiral strise. 



Group of H. albicans. 



A large oval smooth shell is the following, having obsolete spirals. 

 It probably has no especial relationship to H. cracherodii, but shows 

 the same curious parallelism in characters exhibited by a number of 

 Kew Zealand and Australian shells belonging to various families. 



H. albicans Quoy & Gaimard. PI. 5, fig. 27. 



Shell large, oval, distance of apex from margin one-sixth to one- 

 eighth the length of the shell ; nearly smooth but with obsolete 

 spiral lirre ; orange or orange-scarlet, radiately striped with contin- 

 uous white flames ; perforations very small, about 12 in number. 



The outline is oval, right and left margins about equally curved ; 

 back convex, rounded, not angulated at the row of perforations. It 

 is rather thin, the coloration consisting of continuous oblique stripes 

 of scarlet and whitish. Surface sculptured with nearly obsolete 

 spiral threads and cords. Spire moderately elevated, whorls about 

 1\. Inside silvery, the nacre almost smooth, but showing traces of 



