384 MARINE INVERTEBRATES 



peake Bay, but the transplanting of oyster-spat thence to Long Island 

 Sound has introduced the enemy at the same time. The species has a 

 wide range from Florida to Cape Cod, and locally north of that point ; 

 in fact, it may be counted upon to appear wherever there are oyster- 

 beds. The shell is dingy gray in color, and its whorls are crossed by 

 a dozen or more rib-like undulations, and numerous revolving striae. 

 The anterior canal is produced, and is yellowish-brown within. Length 

 under an inch. 



GENUS Eupleura 



E. caudata. A curiously flattened shell which has close 

 family connections with that last described. The peculiarly flat 

 appearance is due to the fact that there is a rather wide varix 

 upon each side of the shell. It is a small species, never more 

 than an inch in length, dingy gray, with longitudinal undula- 

 tions upon the whorls, and a long, narrow anterior canal and 

 crenulated lip. The animal is white and yellow, and is nota- 

 ble for its activity. Found from Maine to Florida, about low- 

 tide mark. 



On the west coast of the United States occurs a striking devel- 

 opment of a group of the Muricidce of a curious foliaceous ap- 

 pearance, belonging to the genera Pteronotus, Ocinebra, and 

 Ce-ostoma. 



GENUS Pteronotus 



P. festivus. The shell is marked by three well-raised varices upon 

 each whorl, which are reflexed backward ; between each varix is a 

 rounded knob. All is covered with numerous spiral lines of sculpture, 

 which upon crossing the varices are frilled. The aperture is oval and 

 white within ; the anterior canal is entii-ely closed and is reflexed slightly 

 over the back. Length two inches ; color dingy white. Found on the 

 southern coast of California. (Plate LXXII.) 



GENUS Ocinebra 



O. poiilsoni. This has the same dingy white color as the species last 

 described. Its plan of sculpturing is somewhat different and consists of 

 a series of rounded varices, about nine to a whorl, crossed by spiral lines. 

 The anterior canal is open, and just within the white aperture, upon the 

 inner side of the lip, is a series of five or six little round teeth. This species 

 frequents the waters near San Diego, and sometimes grows to be two 

 inches in length. (Plate LXXII. ) 



O. lurida. A much smaller species than the last, being not more than 

 one half to three fourths of an inch in length. Very common at Mon- 

 terey and in San Francisco Bay. It is strongly marked with spiral lines 

 covering the longitudinal undulations usually found in this genus, but 

 which are less prominently developed in this case. 



There are several species of small ocinebras upon the California coast, 

 but they are not easily determined without a more critical examination 



