68 THE NAUTILUS. 



water are the smallest and most inflated, and their beaks are com- 

 monly more prominent ; some of them have crowded striae of growth. 

 New Philadelphia, O., Sept., 1896. 



ISAAC LEA DEPARTMENT. 



[Conducted ID the interest of the Isaac Lea Conchological Chapter of the Agassiz Associa- 

 tion by its General Secretary, Mrs. M. Burton Williamson.] 



NOTES ON SOME SHELLS OF PTJGET SOUND. 



[Extract frem the report of Mrs. M. Drake. From the Transactions of the Isaac Lea 

 Conchological Chapter for 1895.] 



In January, I went out to Gig Harbor, but the tides were not 

 good and I got few shells. About seventy Pterorhytis foliatux were 

 found at Point Richmond, some of them quite large with rich brown- 

 bands. We find this shell at quite low tide, clinging to the rocks 

 in much the same way as Piirpura crixpata, and its operculum is 

 very much like that of the Piirpura, only it is of a deeper brown 

 and stronger. A horn is on each one of its three wing-like varices. 

 As it grows in strong currents, its shell is heavy and not easily 

 broken. 



I also collected (dredged) some young Peden hastcdus which are 

 plain in color, and without the lovely spines of the adult. We 

 found them attached to kelp. The young are attached to kelp by 

 their byssus, while the larger ones are free swimming, and can move 

 quite rapidly through the water. We take most of them in several 

 feet of water, with a dip-net, at low tide. 



We find four species of Saxidomus, they are Scuridomus nitttnl/i, 

 8. sqiialidtts, S. aratus and 8. brevisiphonana. As the last name 

 indicates, that species has short siphons, and it is more rounded, 

 shorter and has a stronger shell. I found two species of (.'artlimn 

 at Brown's Point, one being in somewhat deeper water than the 

 other, with a rougher, heavier and plainer shell. The animal is also 

 different. By the way, how can conchologists be sure of the differ- 

 ences and resemblances of closely allied shells without studying the 

 living animals?' I am sure I could not have seen so much beauty 



1 Here is where we amateurs may add to the general knowledge by studying 

 the animal in its habitat while it is vet alive. M. U. \V. 



