HALIOTIS. 101 



more or less tubercled, especially on the earlier part. There are 

 usually low wave-like radiating folds on the inner part of the body- 

 whorl, but these are often absent. There is great variation in the 

 degree of elevation of the spire. Inside silvery, with red and green 

 reflections, strongly spirally grooved. Columellar plate wide, flat or 

 a little concave, scarcely truncated at base. Cavity of spire rather 

 deep, the rib bounding it having a shallow furrow around it. 



Length 50, width 30, convexity 11 mill. 



Length 53, width 33, convexity 11 mill. 



Ceylon and the Red Sea to Mosambique ; Mauritius. 



H. pustulata KEEVE, Conch. Icon., f. 52. WEINKAUFF, Conchyl. 

 Cab., p. 45, t. 1 7, f. 5-8 (as " pustulosa"). SOWB. Thes. Conch, v, p. 

 28, f. 112. MARTENS, Mobius' Reise n. Mauritius, Moll., p. 298. 

 H. alternata So WEBBY, Thes. Conch, v, p. 23, f. 51. 



This is an excessively variable form, allied to H. varia, but dis- 

 tinguished by the coarser and flattened cords of the surface. The 

 following forms I believe to be mere varieties ; the development of 

 the spiral sculpture is excessively variable and irregular, and can- 

 not be depended upon for specific distinctions in the group of spe- 

 cies immediately surrounding H. varia. 



Var. SCUTULUM Reeve. PI. 18, fig. 5. 



Shell convex, spire depressed, rather concealed, spirally faintly 

 ridged, ridges flattened, waved, here and there larger ; 6 holes open ; 

 olive-brown very beautifully articulated dotted and spotted with 

 green. The ridges of this shell have a peculiar undulating charac- 

 ter, and toward the middle of the shell are arranged one broad 

 and three narrow alternately. (Reeve.) 



If. scutulum REEVE, Conch. Icon., f. 63. 



Var. PEBTUSA Reeve. PI. 8, fig. 45. 



Shell oblong-ovate, spirally posteriorly very finely grooved, grooves 

 pricked, anteriorly faintly ridged, grooves and ridges rather irregular 

 and waved ; 6 perforations open ; exterior ruddy-brown with a few 

 yellowish zigzag streaks near the spire, interior brightly iridescent. 

 One half the shell is sculptured with faint pricked grooves, the 

 other with fine waved ridges. (Reeve.) 



H. pertusa REEVE, Conch. Icon., f. 61. 



