BULLA. 201 
exists between longirostrata and birostris, in the latter only of 
which is a denticle present. Moreover, as no notice has been 
taken by Linneus of the figure (217) of the traditional birostris in 
the first volume of Martini, whose engravings have been else- 
where cited throughout the revised copy, it is probable that the 
delineation was advisedly rejected. 
Bulla spelta. 
This species was far better defined in the tenth than in the 
twelfth edition of the ‘Systema;’ for the characters of the suc- 
cinct diagnosis were not contrary to those of the single illustra- 
tive figure (Gualtier, pl. 15, f. 4) referred to, and both, more- 
over, harmonise with the features of a shell from the authenti- 
cated locality. This combination distinctly poimts out the 
Ovulum secale of Sowerby’s ‘Species Conchyliorum’ as the 
true representative of the Linnean shell, and that well-known 
species has been hence termed O. spelta in Philippi’s ‘ Enu- 
meratio Molluscorum Siciliz.’ An important change is ob- 
servable in the twelfth edition: the “utrinque attenuata” has 
been altered to “utrinque obtusiuscula,” and three additional 
references have been annexed to the synonymy. Of these, 
Petiver’s drawings (not 1, 38, as misprinted, but 2, 3; figure one 
represents Bulimus decollatus, for which it has been quoted by 
our author) are designed for O. carneum, whose rich colouring 
is opposed to the “alba” of the description; Barrelier’s en- 
graying is too wretched even for conjecture ; Ginanni’s 95, C, 
bears some slight resemblance to spelta proper. The shell in- 
tended in the twelfth edition was probably the O. obtuswm of 
Sowerby’s Monograph; at least, that is the only specimen in 
the Linnean cabinet which at all agrees with the altered de- 
scription. The expression “ vix birostris, sed magis patula” is 
not very well suited to it, but is peculiarly applicable to the 
spelta of the Mediterranean. ‘The absence of any denticle 
upon the upper end of the inner lip in the Ovulum selected in 
the ‘Species Conchyliorum, as the representative of this 
Bulla, is fatal to its claims, since the presence of that charac- 
teristic (“‘denticulo obsoleto ad apicem columelle”), however 
2D 
