116 EOCENE MOLLUSCA. 
lanceolata, bisulcatd ; ano ovato, obtuse circumdato, in medio prominenti ; apicibus depressis, 
approximatis ; marginibus integris. 
Shell elongately ovate, smooth, thin, and slightly convex or tumid, mequilateral ; 
pedal region ovately rounded ; siphonal region obliquely truncated, or very obtusely 
rostrated; lunule elongated with a central elevation or ridge; anal region ovate and 
centrally elevated ; beaks depressed ; margins smooth. 
Length, \ inch ; height, 5 an inch. 
Localities. Barton (Edwards). 
This species has considerable affinity with WV. d¢svlcata. It appears to differ in being 
of a more elongated form, and in having the siphonal region more inflated ; the whole 
shell appears to be more regularly convex, and the concentric lines or lines of growth are 
more distinct than they are upon JV. disu/cata. 
This shell, perhaps, was not covered with a very thick epidermis, as there are no 
remains of it upon any of the specimens I have seen, and the beaks are not eroded. 
14. Nucuta pratoneata, S. Wood. ‘Tab. XIX, fig. 1 a, 3d. 
Spec. Char. N. testd ovato-elongatd, prelongatd, tenut, levigatd, convexiusculd, 
inequilaterali ; pedi-regione ovato-rotundata ; siphoni-regione brevi, subangulata ; lunulé 
lanceolatd, bisulcatd; ano ovato, circumdato, in medio prominenti; apicibus depressis, 
approwimatis ; marginibus crenulatis. 
Shell ovately elongate, thin, smooth, and slightly tumid, inqnilateral ; pedal region 
roundedly ovate ; siphonal side short and slightly angulated ; lunule elongate, with double 
shallow depression ; corselet slightly prominent in the middle; beaks depressed ; margins 
crenulated. 
Longest diameter, \ inch nearly, 
Locality. Bracklesham (Hdwards). 
Only two or three specimens of this species have come under my observation ; they 
somewhat resemble in form JV. prelonga, but the crenulated margin will distinguish them, 
and there is a difference, also, in their comparative lengths. This shell seems, also, to be 
more iridescent than JV. prelonga, and rather more deep or tumid. 
Two other specimens from the same locality, in Mr. Edwards’s cabinet, have a somewhat 
similar outline, but they have not the basal portion of the anal region quite so much 
extended or angular; they appear, also, to have a more distinct lunule and corselet than 
the one figured (prelongata); and these depressions (lunule and corselet) are divided by 
a small central ridge, which I do not perceive in our figured specimens. I am, however, 
unwilling to separate them, as they otherwise correspond, and future observations must 
determine whether they be the same or different. 
