1068 DENTALIUM. 



Adams's Micro, p. 6S5. t. 14. f. 8. Montagu Test. p. 

 496. Maton and Racket, in Lin. Trans, viii. p. 238. 

 Inhabits the sea near Sandwich. Boys. Among the sand in 



Falmouth harbour. Montagu. 

 Shell about one-eighth of an inch long, and one-third as broad, 

 of a greyish white colour, and striated transversely ; aperture 

 round, a little contracted at the margin, and Montagu says 

 the opposite end is closed, truncated, and furnished with a 

 small round protuberance. 



TRACHEA. 13. Shell curved, sub-cylindrical, and 

 minute, with crowded annular striae ; sum- 

 mit truncated and imperforate. 



Dentalium Trachea. Montagu Test. p. 497. 1. 14. f. 10. 

 Maton and Racket, in Lin. Trans, viii. p. 239- 



Found in sand from Milton in Devonshire, but is extremely 

 rare. Montagu. 



Shell rather more than one-eighth of an inch long, and the dia- 

 meter is about one-fifth of the length ; Montagu says it dif- 

 fers from JJ. imperforatum " by being more arcuated, and 

 a little tapering ; is longer in proportion to its breadth, the 

 margin of the aperture even, and not contracted, and the an- 

 imlations stronger, giving it the appearance of the windpipe 

 or Trachea of an animal ;" the colour is ferruginous brown, 

 becoming paler towards the summit. 



MINUTUM. 14. Shell slightly curved, cylindrical, 

 minute, and smooth. 



Dentalium minutum. Linnaus Syst. Nat. p. 1264. Schroe- 



ter Einl. ii. p. 526. Gmelin, p. 3737. 

 Dentalium glabrum. Montagu Test. p. 497. Maton and 

 Racket in Lin. Trans, viii. p. 239. 



Inhabits the Mediterranean. Linnaus, North coast of De- 

 vonshire. Montagu. 



In addition to a very short specific character, Linnaeus only says 

 that this species is so very minute as not to be discernible 

 with the naked eye, which does not at all accord with his re- 

 ference to Plancus's t. 2. f. 2, and Gmelin has conjectured 

 that Linnseus by mistake described the spire of some minute 

 Echinus : it is, however, by far more probable that D. gla- 

 brum is the species intended, and of this Mr. Montagu has 

 given the following description : " Shell cylindrical, arcuated, 

 smooth, glossy, white, devoid of either striae or wrinkles, and 

 equal in size throughout ; aperture orbicular; the other end 



