54 POPULAR BRITISH CONCHOLOGY. 



P. codulata : shell narrow^ curved, ribbed behind, orange, 

 rayed with red; three-quarters of an inch long. 



II. DiODONTA fragilis has one long and one short siphon, 



both fringed; the mantle open the whole length and 

 fringed. The shell is oval, thin, pale brown, striated 

 and angular at the back ; hinge with two teeth in one 

 valve to one double-tooth in the other ; hgament ex- 

 ternal ; muscular impression strong, with a deep sinus 

 in the impression of the mantle. It is taken near 

 Dublin, in Ireland, and near Tenby, in Wales. 



III. Tellina. — Among many similar genera, the Tellince 

 may be known by a kind of fold in the hinder part of 

 the shell, which is shown by a curve in the line dividing 

 the two valves in the ventral margin ; the ligament is 

 external; teeth one or two central, generally two lateral; 

 muscular impressions not quite equal; pallial impression 

 with a sinus. The animal has very long siphons, quite 

 separate and nearly equal, with plain openings; the 

 fringed mantle is entirely open. These molluscs live 

 in sand or mud, quite under the surface, some distance 

 from the shore. The British species are — 



T. crassa : almost as broad as long, thick, and ribbed in the 

 direction of lines of growth ; pinkish, with pink rays. 



