38 THE NAUTILUS. 



The existence of mollusks in water pipes is no new thing, though 

 it is always interesting, and this is the first instance I have heard of 

 in which any of the Pleuroceridie have such a habitat. M. Locard 

 found 44 species belonging to 13 genera in the water-mains of Paris, 1 

 and that they possessed certain peculiarities, no doubt the result of 

 their environment. These were a diminution in size and decrease 

 of coloration on account, perhaps, of the want of light ; a more 

 slender form, as this would make the least resistance to currents and 

 enable the mollusks to cling more securely to the pipes. The speci- 

 mens of Plettrocera sent by Mr. Lewis did not specially differ from 

 those in the Museum Collection from Davenport, but, as the species 

 had only been noticed at Hannibal a few years, it is probable that 

 there has not sufficient time elapsed in its new environment to pro- 

 duce any important changes. 



Many other cases of mollusks living in water pipes are known, 

 notably that of Dreissensia polymorpha, introduced into England 

 from the Aralo-Caspian region, and it has proven a serious nuisance 

 in the mains of London, Birmingham and Manchester. 



MARINE SHELLS OF PUGET SOUND. 



By Mrs. Marie Urake. From the Transactions of Isaac Lea Conchological Chapter 

 of the Agassiz Association for 1894. 



I have a Glycimeris f/em'i'osa Gld. which I got from Dr. Pomeroy 

 of Vashon Is. It weighed 7} Ibs. when alive, and was dug from a 

 depth of three feet. Its length is 73 inches, width 4} inches. Its 

 longest circumference is I-'!', inches. It gapes widely at both ends ; 

 rarely meets when alive. Its edges are covered with a yellowish- 

 brown epidermis. The pallial sinus, though not very deep, is from 

 k inch to 2 inch wide. Its distinct concentric grooves or lines are 

 slightly irregular. The valves of this shell are strongly bulging. 

 This shell is commonly called " Goe-duck," because it is so deep a 

 burrower. The Indians esteem this shell-fish a great delicacy, and 

 ornament their houses and yards with the shells. It is highly es- 

 teemed as an article of food, though quite difficult to obtain ; one is 

 said to furnish food for a whole family. Star-fish are also found by 

 the hundreds at low tide on the mud flats, and of every hue bright 

 scarlet, peacock-blue, sea-green and paler tints. 



'See NAUTILUS, Sept., 1894, p. 59. 



