TAr>. xvr. 



MYTILUS staonalis. 



Class 6. Vermes. Order 3. Testacea. 



Gen. Char. Animal an Ascidia ? Shell bivalve, 

 rough, generally affixed by a beard of silky fila- 

 ments ; hinge generally without teeth, with an 

 awl-shaped excavated longitudinal line. 



Spec. Char. Shell ovate, rather smooth, gibbous, 

 with a flat space near the hinge. 



'Syn. Mytilus stagnalis. Linn. Si/st. Nat.ed. 13. v. 1. 

 3362. 

 Mytilus maximus planior viridescens edentulus. 

 Schroei.JIusconch. 159. t. \.f. \. 



i HE pair of shells from which these were drawn appear to 

 be unique as British. They much resemble those of My- 

 tilus Cyg7ieuSy but are however more gibbous, and more 

 pointed on one side. There is also a flat space near the 

 hinge towards the broader side. The description, in Linn. 

 Syst. Nat. ed. 13, which follows, agrees nearly with our 

 shell, and we make no scruple of considering them as the 

 same : — " Like M. Cygneus, but the shell Is much larger, 

 being eight inches broad and four and half long, less con- 

 vex*, greenish, with obscure green rays, and the margin is 

 vcllowish brown." In the copy of Schroeter at Sir Joseph 



* This is the only part of the description which dilTers from our shell, wluch 

 is more convex tliau M. Ci/puiu<. 

 VOL. I. D 



