upon the Gevus Scaphura, <^'c. 227 



larity of structure, and thereby forming themselves into natural groups ; 

 and. Secondly, That there are numbers of such groups, of varied 

 degrees of rank, which (having regard to their comparative value, as well 

 as to their relative characters,) do exhibit such wide distinctions from the 

 nearest allied groups with which w€ are acquainted, that I cannot but 

 think that our minds must be influenced by a very considerable degree of 

 fancy, ere we arrive at the conclusion that such groups are but the effects 

 of accident, and that other unknown groups do exist, or have existed in 

 nature, by means of which a gradual and uninterrupted passage can he 

 maintained without the intervention of any hiatus. 



In the present day, an object possessing a peculiar formation is, with- 

 out hesitation, formed into a genus ; subsequently other objects are dis- 

 covered, presenting precisely the same structure, but varying perhaps in 

 size, or merely perhaps in colour. This cannot otherwise be regained 

 than as establishing the validity of the genus, and the propriety of its 

 formation, and that it must, for the present, at least, be regarded as an 

 insulated group. 



And such has been the genus Scaphura^ estabhshed and described by 

 Mr. Kirby in a preceding volume of this work, to whom a single species 

 was only known, subsequently, however, several others have presented 

 themselves, possessing the same singularities of formation, and differing 

 from each other scarcely otherwise than in colour. 



With regard to the generic characters of Scaphura,* of which Mr» 

 Kirby has given such very accurate and valuable details in the second 

 volume of this Journal, (p. 10.) I may be permitted to add, that the 

 Antennse, (of which the length is doubtfully mentioned by Mr, K.,) are at 

 least twice the length of the body in my specimen of Sc. Rirbii; and^ 

 which is the only specimen which I have seen possessing perfect Antennae 

 (this, however, may easily be accounted for, from the very delicate struc- 

 ture of their terminal capillary portion) . The incrassation of the basal 

 joints is not, as might perhaps have been anticipated, a sexual character, 

 since the male, of Sc. Edwardsii, at least, possesses a similar formation. 



* I am inclined to consider this genus as synonymous with that of Penni- 

 corne, of which Latreille merely says, (Fam. Nat. p. 413.) " Sauturelles du 

 " Bresil, k antennes garnies inferieuiement de poils." 



