144 



AMERICAN JOURNAL 



the coast of North America, southwards at least as far as Yu- 

 catan,* where it is very common. 



As doubt is sometimes entertained whether F. perversus is not 

 a variety of F. carica, the writer examined the embryos in the 

 ovicapsules of F. carica, and, among over 500 specimens, no 

 sinistral example was detected The direction of increase seems, 

 therefore, to be coincident with structural characters in those 

 species, and consequently of specific value. 



Several of the extinct species are accepted solely on the 

 authority of Mr. Conrad, no specimens of F. maximus, F. 

 scalarispira and the eocene species being at present accessible. 

 Of those seen by me, I have ventured to refer to the F. contra- 

 rius, the B. adversarium, Conrad, and am also much inclined to 

 consider both identical with F. maximum. The two forms differ 

 only in the direction of growth ; but, as that character has been 

 found constant in the living representatives of the genus, it has 

 been deemed advisable, for the present, to retain the two as dis- 

 tinct. It may be here remarked that observers often urge that 

 a sinistral form is more obliquely wound than a dextral one ; such 

 appearance, however, is generally illusive, the eye being unac- 

 customed to reversed shells ; the reflection of a reversed form, 

 as seen in a mirror, corrects the impression, and renders more 

 easy the comparison of sinistral with dextral shells. 



Although the views of Mr. Conrad have, from a certain 

 necessity, been adopted in some cases, I have had no hesitation 

 in refusing to admit such a nominal species as '■'■Busycon stri- 

 atMwi,"t as no character has been given to distinguish it from 

 the young of other species of the genus, nor probably can any 

 satisfactory diagnosis be given ; the "species " has been based on 

 a specimen little more than an inch long. 



The diagnosis of the genus by Montfort was quite satisfactory ; 

 the armature of the spire, mentioned as a generic character, is, 

 indeed, not common to all the species ; but the introduction of 

 that character by Montfort was legitimate, in view of the mate- 

 rials at his command. His figure, though very rude, is char- 

 acteristic, and represents the columellar fold, which more 

 artistic figures have failed to exhibit. His figure illustrates F. 

 carica, but he has confounded under the name F. eliceans both 

 F. carica and F. jjej'versus, and maintained that the dextral 

 shell was perfectly identical specifically with F. perversus. 



The genus, after long neglect, was revived by Dr. J. E. 



* I have examined a number of specimens collected in Yucatan by Mr. 

 .Arthur Schott. 



f Conrad Am. Journ. Conch , 18G6, p. 69, pi. 3, f. 8. 



