HETEROPHROSYNIDZ. 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, carrymg a small, elon- 
gated, narrow, arcuated operculum, with the muricidal cha- 
racter of the strize 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 Limneade and Bullide, and forms an excellent 
transition-genus to the Pyramidellide, 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 générateur, 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. Tornatel/la has no 
gizzard, but no Bulla is without one. This animal seems 
to hover on the confines of the Bullide, Conovulide and 
Pyramidellide, and has a cross with the Cypreade ; but the 
balance of characters is greatly in favour of its present inter- 
mediate position. 
HETEROPHROSYNIDA, nobis. 
We have constituted this family to receive the genus 
Jeffreysia, 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 Littorinide, and, though much more closely 
related to the Pyramidellide, it could not be deposited there 
without an inconvenient alteration of some of the characters 
2¢2 
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