272 ■ Pub. Puget Sound Biol. Sta. Vou 2, No. 49 



the bottom and sides of the jar, and after a while swim about. Apparently 

 it relaxes to sink, or sinks when relaxed. The means by which the animal 

 reaches the surface is not known. 



The eel-grass offers an excellent feeding ground for Melibe. Here the 

 water is not only calm but abounds in small crustaceous forms of many 

 kinds. Zostera grows in large beds in the bays near the Puget Sound 

 Biological Station at Friday Harbor, Washington. It offers a suitable 

 assembling place for Melibe, where the animals may pair and lay their 

 eggs. At low tide the eel-grass floats on the surface of the water, leaving 

 areas of open water between. In these open spaces these animals collect 

 and copulate. This was observed in the summer of IDli, when the writer 

 first found these animals. The animals were united head to tail in copula- 

 tion. 



The excellent condition of the water offered an ample opportunity to 

 study the manner of feeding. This corresponds rather closely to Eliot's 

 description for M., fimbriata (1902). M. leonina is not so definite in its 

 movements during its feeding as is M. fimbriata, yet a similar method is 

 pursued. Both species have a large hood. In the case of M. leonina this 

 is distended very widely (Fig. 1) when the animal is searching for food, 

 and is periodically contracted into a knob (Fig. 2) when food is obtained. 

 When the hood is open it is tossed sideways and held in a direct position 

 for the capture of small horizontally swimming Crustacea. Melibe is 

 actively predaceous. Its stomach has been found so completely filled with 

 minute Crustacea, such as copepoda, amj^hipoda, and isopoda that it 

 bulged out in almost a perfect sphere. However, ordinarily the stomach 

 only partially distends, with its diameter a little longer than that of the 

 proventriculus anterior to it, or the intestine immediately behind. 



One morning a nidosome was found which had been deposited by the 

 animal during the night. It was a funnel-shaped structure (Fig. 3) and 

 adhered by its small end to the side of the jar. 



When touched the animal gives off a very strong offensive odor. This 

 may be a means of protection. 



Summary 



1. Melibe leonina is an actively predaceous animal; it practically 

 gorges itself, feeding mainly on small crustaceous forms of various kinds. 



2. It occurs close to the surface on Puget Sound from March to 

 August. 



3. Its defense is probably an offensive odor. 



4. It lowers itself to deeper water probably by relaxation of the 

 muscles. 



