CHAP. IV. BANK OF THE MELON VOLUTES. 117 



Now, the melon-shells, forming our genus Valuta, are of 

 this description ; they stand at the head of the whole 

 family ; and we accordingly find their subordinate types 

 are not only the most varied, but the most numerous. 

 Vol. imperialism Scapha, angulata, and magnifica enter, 

 indeed, into their circle; but they do not form the highest 

 point of perfection. This is seen only in the melons, 

 strictly so termed; yet, even here, how great is the 

 diversity of forms ! We have some with a spire alto- 

 gether hid, and the shell devoid of colour, as in Nep- 

 tuni; others with the indication only of a mis-shaped 

 spire, as in V. Cymbium, yet with marbled variegations : 

 another little assemblage has coronated and vaulted 

 spines ; and even among these, the spire is so varied, 

 that in one, V. tessellata, they are compressed, as it were, 

 over an extremely short spire, which they almost hide ; 

 or, as in diadema, they are long, and directed forwards : 

 finally, there is one (V. Broderipia) which deviates so 

 much in its general shape and habits from all others, 

 that it will not strictly arrange with these coronated 

 melons, or with the next type, V. imperialis. Now, all 

 these variations absolutely occur in the compass of a 

 single sub-genus : and we may explain this diversity by 

 supposing that the coronated melons typify the genus 

 Cymbiola and V. imperialis; that the smooth melons 

 are the true representatives of the whole ; and that the 

 V.Broderipia is an aberrant form connecting the coro- 

 nated melons with Valuta imperialis. That such shells 

 as Valuta JEthiopica are much more perfect (abstractedly) 

 in structure than Neptuni and its allies, is unquestion- 

 able : but this does not imply typical perfection ; for it 

 frequently happens in aberrant groups (as the Volutidce 

 is among the Zoophaga), that the typical character rests 

 on very different considerations. 



(106.) It will be needless to go into all the details of 

 the next genus, Cymbiola. Yet it will be satisfactory 

 to see how intimately the types represent those of the 

 Voluta, at least, in their main characteristics. In the 

 following table, therefore, we have selected those species 

 i 3 



