178 TURRITELLID^R. 



his excellent memoir our account of this curious creature 

 is chiefly derived. 



The g-enus appears to have begun, so far as we yet 

 know, during- the Eocene period, since, according to Mr. 

 Searles Wood, a species of it has been found at Hordwell 

 by Mr. Edwards, In later tertiaries several species occur. 



C TRACHEA, Montagu. 

 Tolerably strong, with numerous close-set anuular sulci. 



Plate LXIX. fig. 4, and (Animal) Plate K K, fig. 1. 



Dentalium impcrforatum, Adams, Microscope, pi. 14, f. 8. — Mont. Test. Brit, 

 vol. ii. p. 496. — Maton and Rack. Trans. Linn. 

 Soc. vol. viii. p. 238.— TuRT. Conch. Diction, p. 39. 

 — Brit. Marine Conch, p. 4. — Dillw. Recent Shells, 

 vol. ii. p. 1067. — Wood, Index Test. pi. 38, Dent, 

 f. 12. 

 „ trachea, MoxT. Test. Brit. vol. ii. p. 497, pi. 14, f, 10. — Maton and 

 Rack. Trans. Linn. Soc. vol. viii. p. 239. — Brit. Marine 

 Conch, p. 5, fig. 61. — Dillw. Recent Shells, vol. ii, 

 p. 1068.— Wood, Index Test. pi. 38, Dent. f. 13, 

 Ortliocera imperforata, Fleming, Brit, Animals, p. 237. 

 Odontidiiim rugulosiim, Philippi, Moll. Sicil. vol. i. p. 102, pi. 6, f. 20, and 



vol. ii. p. 73. 

 Brochus tracMformis, Brown, Illust. Conch. G. B. p. 124 (pi. 56, f. 10, bad). 

 „ siriatus, Brown, Illust. Conch. G. B. p. 124, pi. 56, f. 13. 



Although larger than the next species, this too is a very 

 small shell, scarcely exceeding the eighth of an inch in 

 length, which for the most part is to the breadth as five to 

 one. It is subcylindrical, moderately curved, tolerably 

 strong, not transparent, and of a whitish hue, that in the 

 more recent specimens is generally stained with ferruginous 

 or rust colour, in lighter and darker circles. It tapers 

 slightly towards the imperforated end, where the sculpture 

 abruptly terminates in a short projection, which is either 

 simply obtuse, or a little recurved and bluntly attenu- 



