HETEKOPHKOSYNnXE. 387 



"Animal not differing materially from Bulla. Colour white. 

 An oblong foot, a little longer than the shell, truncate in 

 front and auricled; obtuse behind, carrying a small, elon- 

 gated, narrow, arcuated operculum, with the muricidal cha- 

 racter of the strise of increment. The head is flat, divided 

 from the foot by a deep groove coalescing with the tentacula, 

 anteally a little dilated, " medio excisum ?," divided above by 

 a longitudinal mesial furrow, terminating posteally in two 

 lanceolate lobes reflected on the middle of the shell. Two 

 small eyes in the middle of the head." 



This is the only species of the family, and belongs to the 

 bisexual fifth division ; nevertheless it has some alliance with 

 the aberrant Limneadce and Bullidte, and forms an excellent 

 transition-genus to the Pyramidellidts, with which it is in 

 much closer alliance than with Bulla, by the presence of a 

 more developed columellar fold, reflexed apex, corneous oper- 

 culum, pendent organe generateur, and also by bisexuality, 

 instead of congressional hermaphroditism. We may also 

 mention, that no true Bulla exists with an operculum, and in 

 this instance it is of muricidal sculpture. Tornatella has no 

 gizzard, but no Bulla is without one. This animal seems 

 to hover on the confines of the Bullidte, Conovulidee and 

 Pyramidellidte, and has a cross with the Cypr&adee ; but the 

 balance of characters is greatly in favour of its present inter- 

 mediate position. 



HETEROPHROSYNID.E, nobis. 



We have constituted this family to receive the genus 

 Jeffrey sia, as yet of only one species, though one or two more 

 may eventually be added. The reasons for the present pro- 

 ceeding are, that in our judgment it would not have been 

 satisfactory to place an animal with organs so anomalous 

 amongst the Littorinidte, and, though much more closely 

 related to the Pyramidellidee, it could not be deposited therein 

 without an inconvenient alteration of some of the characters 



2 c 2 



