55 



MYTILUS edentuhis. 



TAB. CCCCXXXIX. fig. 1. 



Spec. Char. Elongated, smooth; disk obtusely 

 keelshaped ; beak sharp ; posterior side 

 neariy straight ; no tooth in the hinge. 



V ERY nearly of the same form as the common Mussel, 

 but the beak end is deeper, much more keel-sliaped, and 

 a little curved ; the sides are almost parallel ; the front 

 is rounded, and obtuse ; the hinge line straight. 

 A small siliceous cast from Blackdown. 



MYTILUS lanceolatus. 



TAB. CCCCXXXIX.—/^. 2. 



Spec. Char. Lanceolate, slightly curved, 

 smooth; disk, keel-formed; posterior side 

 flat ; beaks acute. 



A VERY elegantly formed shell ; the anterior side is a 

 regular sweep from the beaks to the front without any 

 angle marking the termination of the hinge ; within each 

 beak is one very long lamellar tooth. 



A siliceous cast found at Blackdown : it enriches the 

 Cabinet of L. W. Dillwyn, Esq. and appears to be very 

 rare, as only one specimen has been found. 



