OF CONCHOLOGY. 159 



peared finely perforate under a power of 100 diameters. The 

 septum and laminae are about one-third as long as the shell. 



This species has so far been found unattached. It is ex- 

 tremely active in its motions when disturbed, and has the power, 

 as described by Mr. Morse, of burrowing in and travelling over 

 the sand by contortions of the peduncle and movements of the 

 setas. Furthermore, the soft parts secrete a mucus to which 

 grains of sand adhere, forming a " sandtube " of an extremely 

 ephemeral nature, which sometimes extends over part of the 

 valves ; resembling in appearance, but not in texture or solidity, 

 the tubes of some Sabelhirian worms. For further details the 

 reader is referred to the forthcoming memoir of Mr. Morse. 



It is found on the south-eastern coasts of the United States, 

 from Newberne to Port Royal. 



? ? Glottidia semen, Brod. 



Lingula semen, Broderip, P. Z. S. 1833, p. 125. 



Habitat. — Isle of La Plata, West Columbia. 



It is possible that this and the following species also, from 

 their outward resemblance to the two preceding, may belong to 

 the present genus. 



? ? Glottidia antillarum, Rve., Conch. Icon. pi. ii, fig. 8, 1861.' 

 JIab. — Martinique, Cuming. 



? ? Glottidia Audebarti, Brod., P. Z. S. 1838, p. 135. Rve., 

 Conch. Icon. pi. i, fig. 5. 



ffab. — Isle de Puna, Bay of Guayaquil ; Cuming. 



Genus LINGULELLA, Salt. 



Lingulella, Salt, Mem. Geol. Surv. of Great Britain, vol. iii, 

 p. 333, 1866. 



Shell resembling Lingula, with a produced neural beak, 

 grooved for the passage of a very narrow pedicel. General form 

 rounded triangular. Visceral area of the interior of the shell 

 more or less strongly pitted. 



Tgpe. Lingulella Davisii, McCoy, An. and Mag. Nat. Hist. 

 viii, p. 405. Dav., Sil. Brach. p. 55, pi. iv, fig. 1 to 16. 



This is the oldest form of Lingulidce known, according to Mr. 

 Davidson. It is from the lower Silurian formation. 



