256 GASTEROPODA OF THE INFERIOR OOLITE. 
so obvious. D’Orbigny had no difficulty in referring them all to the genus Natica. 
Whether there were traces of an umbilicus or not, whether the whorls were 
square-shouldered or round-shouldered, these differences were not accounted as of 
generic importance. Seeing, however, that the genus thus constituted would 
include very divergent forms, he divided it into four groups, of which the fourth 
group, viz. the Prelonge, is characterised by the length of the shell exceeding 
the width. To this by far the larger portion of his Jurassic Natice were 
assigned. 
Genus—Natica, Adanson, 1757; as defined by D’Orbigny, 1852. 
* Shell globular, thick, varying from the depressed to the elongated form. Spire 
usually short. Mouth oval or semilunar, modified by the winding of the spire 
Umbilical region very variable, simple or compound, open or closed by callosities.” 
Morris and Lycett, in dealing with the Naticidze of the Great Oolite, classed the 
round-shouldered forms for the most part under Natica, and the square-shouldered 
forms under a sub-genus—Huspira (Ag.). The following is their diagnosis : 
Sub-genus—Hospira, Agassiz, 1837, as defined by Morris and Lycett, 1851. 
“ Shell smooth, ovate; spire elevated ; of few whorls which are angulated, the 
angles sometimes taking the form of a carina’ . . . . aperture entire, elliptical, 
modified by the angle of the whorl; base wide, rounded ; pillar-lip smooth and 
excavated, outer lip thin and smooth.” 
Mons. Cossmann, in his ‘Contribution to the Fauna of the Bathonian in 
France,” like d’Orbigny, minimises the difference between the round-shouldered 
and the square-shouldered Naticide, but groups the whole under the genus 
Ampullina, Lamarck. This is divided by Dr. Fischer (‘ Manual,’ p. 766) into 
sectiois and sub-genera, one of the latter being Huspira, which he thus describes : 
—“ Whorls swollen or canaliculate at the sutwre ; spire sometimes elevated, wmbilical 
fissure but little indicated or concealed.” 
There can be no doubt that most of the Naticide of our Inferior Oolite might 
be classed under Huspira; but then we are met by this difficulty, that some of 
Lycett’s species, such as Huspira canaliculata, were classed by that author under 
Buspira, whilst others, such as Natica Oppelensis, were classed under Natica. And 
yet no shells can have a better title to be regarded as Huspira than Natica 
Oppelensis, Natica adducta, Natica Lorieri, &e. Moreover, the only species of 
Natica known to me in the Lias of this country, viz., Natica Pelops, D’Orb. 
(N. hbuecinoides, Y. & B., fide Tate) must come under this designation. In the 
1 The portion of the diagnosis framed for the admission of “ Euspira” coronata is omitted. 
