348 SPECIES OF THE SYSTEMA. 
Gurbo exoletus, 
Some years ago the numerals 561 (the number in the tenth 
edition of the ‘Systema’ which corresponds with 644 in the 
twelfth) were plainly visible upon two specimens of the Tur- 
ritella bicingulata of Lamarck (Kiener, pl. 8, f. 2): at present 
they are faintly legible upon one alone. Hence Dillwyn, whose 
Turbo exoletus is identical with the shell last mentioned, was 
not wrong in his determination of the Linnean type. 
Notwithstanding the existence of these shells it is not just to 
alter the specific epithet bicingulata on this account (Turbo cinctus 
of Donovan was, however, prior to the Lamarckian name), since 
the figure of Bonanni (the sole drawing referred to) being in 
accordance with the short diagnosis, the united pictorial and 
descriptive characters fully define and illustrate a species, of 
which we find an excellent representation among the Turritelle 
of Kiener (TJ. exoleta, pl. 7, fig. 2, a). Where the essential 
features of a species have been adequately indicated by an 
author, I do not think that even the discovery of his type 
should disturb a generally accepted recognition ; especially in 
the present case, where “ carinis distantibus” cannot be affirmed 
of the Linnean sheils. 
Gurbo teredra. 
Lamarck has accurately divined the Linnean species, for his 
Turritella terebra corresponds very fairly with the specimen 
marked as such by the hand of our author, which has been 
characteristically enough portrayed as Turbo Archimedis in 
Mawe’s ‘Introduction to the Linnean System of Conchology,’ 
plate 28, f. 8. Making due allowances for the imperfection of 
the earlier drawings of natural-historical subjects, the figures 
referred to in the tenth edition of the ‘Systema’ are tolerably 
expressive of the shell intended. Those of Bonanni and 
Gualtier are the most characteristic, those of Argenville and 
Rumphius were probably meant for it likewise; Columna’s 
