UNIVALVE MOLLUSKS 123 



large specimen of this shell. You will notice that 

 the aperture is extremely large, the spire depressed, 

 and the whole shell quite like a bubble. 



Haminea virescens^ Sby., the Green Bubble-shell, 

 is smaller than the last, and has a very short body- 

 whorl, while the outer lip is greatly extended. The 

 animal that it is supposed to protect is much larger 

 than the shell, however, and its delicate, greenish 

 covering can give it but a scant defense. This spe- 

 cies is found sparingly upon mossy rocks on the 

 southern coast. 



In 1863 three large specimens of Aplysia calif or- 

 nica^ Cooper, the California Sea-hare, were reported 

 as found on San Pedro beach after a storm. One 

 of these was fifteen inches long and hve inches wide. 

 Their stomachs were full of seaweed. The soft 

 creatures have no visible shell. 



Pleurobranchus calif ornicus^ Dall, the California 

 Side-gill, also comes from San Pedro. The animal 

 is oval and flattened and has a distinct head. The 

 shell is a thin white scale, concealed in the mantle. 

 The gill is single, feather-shaped, and is placed on 

 the right side between the mantle and the foot. The 

 animal is waxy white in color, about an inch long, 

 while the little shell is half that length. 



Somewhat similar in their anatomy to the last few 

 species are the Sea-slugs, which form a great group 

 of naked mollusks. While they have no shells they 

 are far from being without interest. Their bodies 

 are often very brilliantly colored, so that when they 

 are alive and moving they are among the most beau- 

 tiful objects of the sea. You will find them on sea- 



