174 ^f' William Wood's Obfer vat ions on the 



Fig. 11,12. The fame magnified, (a.b) Two teeth which receive be- 

 tween them the triangular tooth (c). (d) A fmall 

 tooth which pafles on the outfide of (a). (e. e. e, e) 

 Lateral teeth. 



13, T4, The hinge of the Tdlina rlvalis. 



15, 16. The fame magnified, (a.b) Two teeth which unite, and 

 are continued to form an arch for the reception of 

 the triangular tooth (c),.on one fide of which is a fmall 

 tooth (d). (e. e. e. e) Lateral teeth. 

 17,18,19. Hinge of the Tellina b'imaculata, 



20,21. Tellina fcrvenfis. (a.b) Two eredl teeth. In my fpecimen, 

 one is plain, the other notched, (c) A fmall ridge di- 

 viding a depreffion by the fide of (a). 



Tab. XVL 



I, 2. Cardium acukatum. (a. a. b. b) Four ere£l teeth which 



lock together when the fhell is clofed. (c) A remote 



tooth which fits between (d. e), while (f ) receives its 



oppofite, (g). 

 3, 4, MaBra lutraria. (a) The great tooth. (b)The fpoon-fliaped 



cavity, (c) The place which receives the great tooth. 

 5, 6. MaSira bians. (a) The eredl tooth, (b.b) The great cavity. 



(c. d) Two teeth which receive (a) between them. 



(e) A fmall cavity for the grooved tooth (d). (f.f ) A 



narrow fulcus- 

 7,8. Maclra fliillorum. (a) The triangular tooth, (b) The re£t- 



angular one in the oppofite valve, (c c) The cavity 



for the cartilage, (d. d. d. d) Remote teeth- 

 g, 10. Ma'dra alba of the natural fize. 

 21,12. The hinge of the fame magnified, (a. a) The fpoon- 



fhaped cavity, (b) A fmall tooth, (c.c) Remote teeth. 



Fig. 



