NATICA. 263 
impressed ; the spire is elevated, acute, the last volution being very large; the 
aperture is ovate, oblique, the anterior side rounded, the posterior side acute, 
the length exceeding a moiety of the entire shell; the columella is rounded, 
thickened, and there is no umbilicus.” 
Relations and Distribution—Lycett says that this species differs from Natica 
imtermedia in having “‘a more elevated acute spire, more deeply depressed sutures, 
and a more globose ultimate volution.” It is a more elegant shell than Natica 
Dundriensis and of smaller habit. Moreover the sutural ledge (méplat) is so 
narrow that the shell scarcely comes within the definition of Huspiroid ; still it has 
a sutural ledge and not a round shoulder, and is very slightly canaliculate. The 
type is almost the only specimen known. I have one other from the Parkinsoni- 
zone of Lodge Hill near Castle Cary. 
199. Natica Basocrnsis, d’Oréigny, 1850. Plate XX, figs. 13 a, 13 b. 
1850. Narica Basocensts, d’Orbigny. Prod., i, p. 264. 
1852. — — _ Terr. Jur., ii, p. 189, pl. cclxxxix, 
figs. 1—3. 
1873. Evsrrra Basocensts, d’Orbigny. Tawney, Dundry Gasteropoda, p. 5 (13), 
pl. i, fig. 4. 
2? Syn. Narica Proraviensts, d’Orbigny. Terr. Jur., ii, p. 191, pl. cclxxxix, 
figs. 8—10. 
Bibliography, §ce.—In grouping NV. Bajocensis and N. Pictaviensis together we 
seem to ignore d’Orbigny’s distinction with reference to the presence or absence 
of an umbilical fissure. Oppel (Juraform., p. 384) regarded the Burton Bradstock 
fossil as N. Pictaviensis. It is the exception to find an umbilical fissure in any 
Dorsetshire specimen. Mr. Tawney united them. It may be worth remarking 
here that his fig. 2 represents so abnormal a form that one would hesitate to 
place it under N. Bajocensis. Accepting the view that the numerous and well- 
preserved little Naticas of Burton Bradstock should be grouped under one species, 
the following is the diagnosis. 
Description: 
- Spiral angle : . 60°—68°. 
Height of body-whorl to suite shell, ‘from . 60—63: 100. 
Length of adult individuals. : . 23—28 mm. 
Shell Euspiroid, much longer than wide, oval, and usually without umbilical 
fissure. Spiral angle regular, apex very sharp, whorls from six to seven, smooth, 
slightly convex, flatted at the top, and deeply canaliculate; sutural ledge narrow. 
Body-whorl rather compressed. Aperture semilunar with but little callus. 
