148 SHELLS AND SHELL-FISH. PART I. 



are the most important object to be illustrated ; while 

 the mere collector has no additional help to the no- 

 menclature of the species, more than he now has-. 

 Long and procrastinated attention to these beautiful 

 shells, together with the invaluable delineations of their 

 animals by M. Quoy, has now enabled us to give the 

 following exposition of the genera and sub-genera.* 



Analogies mid Characters of the Sub-genera of Conus 

 and CoRONAxis. 



CONUS. CoRONAXIS. 



Types of the Sub- nh^.-^^f.-^ ^f^^^i. Types of the Sub- 



genera. Characters of each. '^genera. 



Shell not coronated. Shell coronated. 



C. litteratus. f Shell ponderous ; basal whorl not ^ n. „ , , . 



Virgo. \ contracted near the suture; ^'^'^f'^'f"!,,, 



generales. C spire in general flattened. J "^'^'^O'^^"^- 



striatus. C Shell ponderous ; basal whorl con- T 4-.„„ „/„„ 

 stercus-mijscarum,< traded near the suture: spire > ^"^" „. 



amraeralis. I short, pointed. 5 *^'^do-nulli. 



bullata. r Shell light; basal whorl ventri- i 



textile. 3 co.se ; aperture effuse ; the base f j, , . 



auratus. "i hardly notched; spire short, f ■^ 



aulicus. (. pointed, concave. J 



nussatella. ( Shell sub-cor>ic, cylindrical, trans- '^ 



glans. X versely grooved ; spire elevated, > Asper ? 



terebra. t thick, convex, generally obtuse. 3 



amadis. r Shell conic, light, often trans- ^ 



grandis. } versely striated ; spire concave, ( < . ,-, • 



duplicatus. \ elevated, and pointed; oute^H"^^'^^^""'^"""^- 



australis. L lip deeply sinuated above. 3 



This, perhaps, is one of the most remarkable instances 

 of analogy yet brought before the reader ; inasmuch as 

 the characters used as analogies are those only by which 

 the shells of each group, or sub-genus, cf Conus and 

 Coronajcis, can be defined. Nothing additional, in fact, 

 can be added to separate, for instance, the sub-genus of 

 Conus, whose type is C. litteratus. from its represent- 

 ative, C. marmoratus, in the genus Coronaxis : so per- 

 fect are these resemblances, that we do not actually 

 know where the two groups join and unite. As to the 

 circularity of each, there cannot, we apprehend, be the 

 least doubt; for the intervening shades of difference are 

 so gentle, that we hardly know where one type ends, 



* The names of the types are in Italic ; those of the annectant species ia 

 Roman. 



