454 MOLLUSCA. TEREDINADyE. Teredo 



Gen. CYRENA. — Suborbicular, with three primary teeth in 



each valve, and transverse lateral teeth ; ligament on the 



longest side. 



1. C pulckra. — Suborbicular convex, smooth, slender; porteriorly tmn- 

 cated ; one sharp-edged and two bifid teeth in each valve ; lateral teeth 

 plain and obtuse.— Cyclas pulcher. Sower. Min. Conch, t. Dxxvii- f. 1. — 

 Hampstead, Isle of Wight, Professor Sedgwick. 



TEREDINAD.^. 



Gen. CXXXI. TEREDO. Ship Worm.— SheU orbicular, 

 hemispherical, eqviivalve ; liinge witli a long curved tooth 

 in each valve, inserted under the margin ; ligament imper- 

 fect, the tube open at both extremities. Burrowing in 

 wood. 



* The em'-shaped process on the inside of the valves, at the 

 outer angle under the hinge, having the inner margin de- 

 tached, and forming a straight transverse edge, and the out- 

 er margin much reflected. 



548. T. hipinnata. — Accessorial appendages long, linear, and 

 feathered ; an oblique rib on the margin above the teeth. 



Tzirt. Corich. Diet. 184, t. xi. f. 38, 39, 40.; Biv. Brit. 15 — In drifted 



timber, Exmouth. 



Diameter upwards of three quarters of an inch ; tube simple ; appendages 



about the tenth of an inch in diameter ; silvery white, with numerous {learly 



tubercles, the outer half with verticillate, lanceolate, fringed filaments. — 



This is nearly allied to T. palmulatus of Lamarck. 



549. T. malleolus. — ^^Accessorial appendages transverse and 

 mallet-shaped, with a slender point rising like a handle from 

 the middle. 



Turt. Biv. Brit. 255. t. 2. f. 19.— Drifted timber, Torbay. 

 Diameter about a quarter of an inch ; strije on the triangular processes re- 

 mote ; the tube consists of a slight testaceous deposit on the surface of the 

 chamber, the termination of which is slightly semiconcamerated. 



** The ear-shaped process with the inner margin on the in- 

 side furnished with a rib only, and not a detached margin, 

 and the outer edge is not reflected. 



550. T. navalis. — Accessorial appendages elongated and 



spoon-shaped. 



Linn. Syst. i. 126? — Penn. Brit. Zool. iv. 147- Mont. Test. Brit. 52?. 

 Home, Phil. Trans. 1826, 278. t. xii. f. 3. Turt. Biv. Brit. 14. t. ii. 

 f. 1, 2, 3.— In timber exposed to the sea; the scourge of shipping. 



