ZOOLOGY : MARINE INVERTEBRATES. 77 



specimens cap be obtained frequently. Petrkola pholadiformis is 

 present on this beach in considerable numbers. The isopod Idotea 

 caeca is very common, as are also other species of Idotea. The 

 strand sometimes is covered with tlie curious trails made by the 

 first mentioned species. 



Many of the shells are more perfect than on Revere beach, 

 but the variety is not so great. 



NAHANT NECK. 



Boute. — By rail, Boston and Maine road from North Union station to 

 I.ynn ; fare $.20. By barge or electrics to beacli. 



Bg electrics, from Scollay square to Lynn (Lynn & Boston cars) ; 

 change to Beach car. 



By bicycle, tlirough Chelsea to Lynn, 12 miles; follow car tracks to 

 beach, 1 mile. 



This bar, reaching southwaixl from Lynn and tying the Nahant 

 islands to the mainland, has an open sea-beach and a harbor-beach, 

 "giving a difference of fauna on the opposite sides. In spite of this 

 fact, the animal life found here differs comparatively little from 

 that of Itevei-e beach ; for the great length of that beach and the 

 diversity in character of the material composing it produce a great 

 variety of physical environments, and hence cause a diversified 

 fauna. 



Among the rarer shells found on Nahant beach after storms are 

 Glycymeria siliquu, Ceronia arctata and Pecten tenuicostatus. The 

 first of thes« is recognized readily by its elongated oval form and 

 its black, dense and shining epidermis. Ceronia arctata may be 

 known by its short posterior end, and Pecten tenuicostatus by its 

 large size and smooth surface. 



Worms and other burrowing animals are plentiful on the Lynn 

 bay side of the neck. Among gephyreans, Phascolosoma gouldii 

 always may be found at low tide by digging in the sandy mud. 

 Of polychsetes, Clymenella torquata is found also in the mud of 

 this beach at low tide. Amphitrite ornata is one of the most beau- 

 tiful marine worms living on these beaches. It may be obtained 

 in the mud at low tide, the position of the animals being marked 

 by the holes in the sandy mud.' It may be recognized by its blood- 

 red gills and numerous long flesh-colored tentacles. It constructs 

 tubes from mud and sand. Several species of Nereis occur also 



' Noted by Dr. Parker and Dr. Davenport. 



