194 MACTRA. FLAT-SIDED COCKLE. Cl. VI. 



6. SUBTRTW-Zz'ra. Tr. viii. 71. t. \. f. 10. M. stultorum. Br. Zool. iv. 



cata. Mont. Test. Br. Q3. id. Sup. Q2. 



37- t.27.f. 1. 



* M. with a smooth, strong, triangular shell, 

 beak more prominent than common. Tab. Iv. 



&■ i. 



7. listeri. Got. Zm. 3261. Venus borealis. Br. Zool. iv. 



Zzn. 7V. viii. 71. 96. 



M. compressa. Mont. Test. List. Angl. t. 4. J". 23. 

 Br. 96. 



M. with thin shells much compressed, marked 

 with slender concentric stria. Length one 

 inch and a half, breadth near two inches. 



8. tenuis. Lin. Tr. viii. 72. Mont. Test. Br. 572. id. 



Sup. t. 17. /• 7. 



* M. with a flat equilateral shell, somewhat 

 triangular ; the hinge-tooth in one valve forked, 

 with the side teeth distant -, diameter a quarter 

 of an inch. 



At Southampton and Weymouth. 



