Hinges of Briiijh Bhahe Shells, 175 



Fig. 15, 14. The hinge of the Dorux Trunadus. 

 > 15, 16. The fiimc magnified, (a) A thick lulcatcd toolh received, 



when the ihell clofes, between (b. h). (c. c) Marginal 



teeth. 



: Tab. XVII. 



I, 3. Vetms ijlandica. (a) The great tooth which locks between 

 (b. b), while the rugged tooth (c) fits into a hoUovv^ 

 within the fmall tooth (d). (c. e. c) Remote teeth. 

 3, 4. Venus Chione. Befides the two ftrong teeth in this llicU, 

 , (a) and (b), there is a third, (c), which pafTcs into the 

 cavity (d), (e) A tooth grooved longitudinally. 

 5, 6. Fenus verrucofa. (a. b) Two thick teeth receiving (c) be- 

 tween them, (d) A large tooth which pafTes on the in- 

 fide of (c). (f J K thin tooth in the direftion of the car- 

 tilage. 

 '],^. Venus GalUna. (a.b) The two principal teeth, (c.d) Two 

 fmaller ones, of which (d) is plate-like, (c) A marginal 



tooth. 



9, 10. Venus exo/eta» (a) An ere6l tooth which Jocks between 

 (b. b). (c) A thick channelled tooth received be- 

 tween (d. d). 

 II, 12. Venus decnjfata. (a) The two cleft teeth in one valve. 

 Cb) The fa i^e in the oppofiLe. (c) The plain tooth. 

 13, 14. Thi> Ihell is provided with a beautiful pe(5linatcJ hinge, 

 confifting of three teeth in each valve, Theie teeth 

 are placed in the mod regular order, and the mid- 

 dle one, I believe, is conftantly grooved. Frequently 

 there is a channel in one of the other teeth, and fome- 

 times, though rarely, we meet with it in both. 

 When this fpecies is found with only two teeth in one 

 8 valve 



