68 GDIDE TO LOCALITIES. 



By electrics, from Scollay square by Lynn and Boston railroad, 

 Revere Beach car. 



By bicycle, from Scollay square to Chelsea ferry, foot of Hancock 

 street, via ferry to Chelsea, thence out Broadway to Beach street, which 

 latter leads to the beach. Walk along beach and return from Point of 

 Pines station, near the northern end of the beach. 



Along the upper beach line, reached only by the storm waves, 

 may be found usually an association of deep-water animals brought 

 there during northeasterly storms. Among the molluscs, Lunatia 

 heros may be mentioned as the commonest gastropod, the large 

 white subglobose shell of this species usually being a conspicuous 

 object. This shell by no means is confined to the upper part of 

 the beach, but occurs all over it, and frequently is very abundant. 

 Not uncommonly the living animal will be found in the shell, having 

 been left on the strand by the retreating tide. The "egg collars " 

 of this species are plentiful on the beach in mid-summer. Each 

 consists of " a mass of sand glued together into the shape of a 

 broad bowl, open at the bottom and broken at one side. Its thick- 

 ness is about that of an orange-peel, easily bent without breaking 

 when damp, and when held up to the light will be found to be 

 filled with cells arranged in quincunx order. Each of these cells 

 contains a gelatinous egg, having a yellow nucleus, which is the 

 embryo shell." 1 



The larger empty shells of Lunatia heros are often reposito- 

 ries of a variety of more or less sedentary animals. Hydractinia 

 polyclina not infrequently encrusts them, although the majority of 

 specimens of the hydroids thus obtained are worthless. Crepi- 

 dula plana and C. fornicata are to be found usually on such 

 shells, the former on the inside. Young specimens often may be 

 obtained. Our eommon limpet, Acmoza testudinalis, is found also 

 clinging to these large gastropod shells. In addition, various spe- 

 cies of encrusting bryozoans may be found on these shells. Shells 

 of L. heros of all sizes may be obtained readily during a short walk 

 on the beach, at almost any time. The small checkered variety L. 

 triseriata is not uncommon on the lower portion of the strand. 



A species which may be mistaken for L. heros, and which is found 

 occasionally on this beacli, is Neverita duplicata. This is distin- 

 guished by its more depressed spire, and by the strong callus 

 which partially or entirely covers tlie umbilicus. 



1 Binney and Gould, pp. 339, 340. 



