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130 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
Argina pexata (Say) Gray. Ver., Inv. V. S., p. 692, 1874. Gould, Inv. Mass., II, 
p. 147, 1870 (Area). 
Collected on the beach at Provincetown (S. I. Smith, 1872). 
Mytilus edulis Linné. Gould, Inv. Mass., I, p. 183, 1870. Ver., Inv. V. S., p. 692, 
1874. : 
Very abundant, shore, piles of wharves, attached to floating fucus, &e. 
Modiola plicatula Lam. Gould, Inv. Mass., Il, p. 188, 1870. Ver., Inv. V. &.. 
p. 693, 1874. 
Very abundant on the flats near high-water mark. 
Crenella glandula (Totten) Adams. Gould, Inv. Mass., II, p. 194, 1870. Ver., Inv, 
V.S., p. 695, 1874. 
A few fresh, but not living, shells were obtained from the beaches at 
low water. Provincetown, at low water (Stimpson, Shells of N. Eng- 
land). This species was first Known to Totten, its describer, from Pro- 
vincetown. ; 
Pecten irradians Lam. Gould, Inv. Mass., II, p. 199, 1870. Ver., Inv. V. S., p. 695, 
1874. 
This species was formerly very abundant in front of the town, in the 
patches of eel-grass just below ordinary low-tide level, but at present 
the full-grown shells are rarely found there. They are, however, still 
very plentiful off the dike in similar situations. The adult shells rest 
on the ground amongst the eel-grass, which at low water becomes 
thickly matted above them, generally quite concealing them. Young 
shells usually adhere to the eel-grass by their byssus. 
Anomia glabra Ver., Am. Journ. Sci., vol. iii, p. 215, 1872; Inv. V. S., p. 696, 1874.— 
A. ephippium, elecirica, squamula, Gould (non Linné). 
Abundant on the flats in front of the dike, but generally of small 
size, attached to dead shells of Pecten irradians, Ensatella americana, &c. 
TUNICATA. 
Molgula manhattensis Ver., Am. Journ. Sci., vol. i, p. 54, 1871; Inv. V. S., p. 699, 
1874. ; 
Abundant near high-tide level, amongst the grass in the pools left 
on the shore at low tide; attached to eel-grass and to floating sea-weeds. 
Also thrown up in immense numbers on the outer beach at Race Point 
during heavy storms. 
Botryllus Gouldii Ver., Am. Journ. Sci., vol. i, p. 211, 1871; Inv. V. S., p. 702, 1874. 
Growing on eel-grass in shallow water and on floating sea-weeds, &e. 
BRYOZOA. 
Crisia eburnea Lamour. Ver., Inv. V.S., p.707, 1874. 
Very abundant on fucus and eel-grass, often associated with Bugula 
turrita; on eel-grass everywhere in shallow water from the dike to 
Long Point, and on facus growing on the piles and floating at the 
surface. ; 
