MELQ. 81 



in fact, the number and direction of the spines vary so in differ- 

 ent species that the distinction appears very arbitrary. 



* * * Spire exposed, not produced, spines erect, spreading. 



M. JETiiiQpiCA, Linn. PI. 23, figs. 17-21. 



Yellowish or orange; generally maculated and tessellated 

 with chestnut, usually in revolving zones. Length, 6-12 inches. 



Indian Ocean, Manilla, Japan. 



In deference to the opinion of the British conchologists, the 

 following " species " may retain their names as stages of variation 

 in the form, coloration and development of spines. It is easy 

 to point out from the numerous excellent illustrations given by 

 Reeve and Sowerb}^ how these authors differ in estimating these 

 so-called species, and how even some of their figures refute their 

 arguments for distinctness. 



Yar. REGIA, Schubert. Fig. 18. 



Yellowish brown, with zones of white blotches. 

 Yar. NAUTICA, Linn T PL 23, fig. 19. 



Spines close-set, converging towards the apex (also towards 

 M. tessellata, very decidedLy). Length, 6-8 inches. 



Yar. BRODERIPII, Gray. PL 23, figs. 20-21. 



Spines very numerous, small. Length, 8-14 inches. 



M. DIADEMA, Lam. PL 23, figs, 22-28. 



Yariable in proportions but generally more narrow than M. 

 JEithiopica; spines few and long. Yellowish, marked with 

 chestnut, frequently forming two interrupted zones connected 

 by irregular or zigzag markings. Epidermis thin, light olive. 



Length, 6-13 inches. 



Indian Ocean; Australia. 



Its narrower coronal, and the few long spines composing it are 

 the best distinctive characters from M. JEthiopica. As in that 

 species I include here as varieties, several forms which have 

 been heretofore considered distinct. M. armata, Lam. (figs. 24, 

 25), is a synonym. 



Yar. DUCALIS, Lam. 



This, and its synonym M. umbilicata, Brod. (fig. 26), are more 

 11 



