THE NAUTILUS. 65 



Semele decisa, Saxidomus nuttalli and other bivalves were 

 equally abundant, but now nearly exterminated. A list of the 

 mollusca from this bed would be extremely interesting, but now 

 hopeless of ever being written, as it is no longer the ideal home 

 for mollusks that it once was. Over 100 Cypraea spadicea were 

 found there in one day, and an equal number of Ranella cali- 

 fornica were yielded by the adjacent sandy beaches. While the 

 shells from this lagoon do not properly belong with the La Jolla 

 list, yet fragments or dead specimens of all noted by Mr. Smith 

 may occasionally be found at La Jolla. 



Tagelus calif or nianus. This is extremely abundant in False 

 Bay and is gathered in quantities for bait by fishermen, and 

 thus the shells are scattered freely all along the La Jolla shores. 



Pedipes unisulcata. Smith reports many of the dead shells 

 attached to sea anemones, but I found it years ago in company 

 with Truncatella stimpsoni on round water-washed boulders in 

 caves near La Jolla. 



Pedipes liratus. This was also found at La Jolla in early 

 days and later by Prof. Kelsey. 



Milnerea minima. Abundant. Attached to the under side 

 of stones. Usually reported as living on the shells of Haliotis. 



Mytilus adamsianus. This was long called M. bifurcatus, later 

 known as M. stearnsi. Smith and Bailey, like many other col- 

 lectors, seem to have overlooked it, probably mistaking it for 

 the young of Septifer bifurcatus which it nearly resembles, except 

 for the absence of the septum. It is equally abundant. 



Mytilus denticulatus. This is similar to the last but much 

 smaller. It is Modiolaria denticulata of former lists, and might 

 easily be overlooked, but is apparently not rare on our rocks. 



Adula diegensis. North of the Scripps Biological Station 

 about a mile north of La Jolla is a rocky beach at the base of 

 high cliffs. Much of the rock is a soft clay stone, and perfor- 

 ated by millions of pholads. In places this species has entire 

 possession, and often they have made their cells so close to- 

 gether that no partitions of rock are left to separate the shells. 



Pholas pacifica. This is one of the pholads found at the 

 above station with others already noted. 



Petricola denticulata. This is extremely abundant in the 



