OBSERVATIONS. 



I received several fine specimens of this shell from Dr. 

 D. H. Storer as inhabiting Cape Elizabeth and Front's 

 Neck, Maine. It is the common "Horse mnscle" of the 

 English collectors and appears to be abundant in the Euro- 

 pean Ocean and Mediterranean Sea. Leach says, "beneath 

 the epidermis the shell is invariably whitish," whilst La- 

 marck says, "Epiderme noiratrc ; test lilas." The shell ap- 

 pears to become more elongated with age. 



Adanson's figure (pi. 15, lig. 1,) generally quoted for 

 this species, is probably altogether distinct ; it is but little 

 more widely rounded anteriorly than posteriorly, and the 

 dorsal angle is much more prominent. Leach quotes My- 

 tillus modiolus, Linn, as a synonym of M. papuana ; but 

 Lamarck and some other conchologists quote it, with 

 doubt, as the same as Modiola tulipa, Lam. 



Laskey in the Transact, of the Wern. Soc. says they at- 

 tain to the length of nine inches ; the largest in my collec- 

 tion is five inches and three fourths long. 



REFERENCE TO THE PLATE. 



The plate represf?nts the exterior and interior views, 

 PI. 45. 



