Found on sand-covered rocks in the lower intertidal, it was originally from the Pacific, occurring in Japan, China, Korea and from Alaska to California. It has since invaded the northeast of the US. It is bushy with deep red-brown fronds, and can grow to 600mm long.

Source:
http://www.seaweed.ie/descriptions/Heterosiphonia_japonica.php

Found this individual dead on the beach at Nahant Beach. They are found on sandy or muddy bottoms from the intertidal up to 91m deep from the Gulf of St. Lawrence to Florida. The shell is long with a conical spire. They have six to seven beaded whorls and are whitish to tan or brown in color. They grow up to 19mm long. This species is a scavenger and can be found on dead fish or other animals (Marine Life of the North Atlantic by Andrew J. Martinez).

Common Name: Sinistral Spiral Tube Worm

Location: Found on a washed up Fucus sp. at Canoe Beach, Nahant, MA.

Habitat: Found in the intertidal on algae, can also be found on hard substrates.

Physical Description: This tube worm grows coiling counterclockwise from its opening. White in color, and (1/8) inches in diameter.

Fun Fact: There is another species of tube worm like this one, but it grows clockwise from its opening instead.

Martinez, Andrew. Marine Life of the North Atlantic: Canada to Cape May. (New York: Aqua Quest Publications, 2003) 156-157.

This horseshoe crab was dead when we found it. It was in a tidal river in the Great Marsh. Atlantic Horseshoe Crabs are found all along the Atlantic coast and in the Gulf of Mexico. Their habitat includes shallow water, but they can also live in deeper water.

Horseshoe crabs can grow up to 60cm, including the tail, but average between 16cm and 20cm in length. Females are typically larger than males. There is a size gradient along the coast with the largest animals being found in the mid-Atlantic region.

Fun Fact:
Horseshoe crabs have hemocyanin instead of hemoglobin, which makes their blood blue.

https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab

Found this individual dead on the beach at Nahant Beach. They are found on sandy or muddy bottoms from the intertidal up to 91m deep from the Gulf of St. Lawrence to Florida. The shell is long with a conical spire. They have six to seven beaded whorls and are whitish to tan or brown in color. They grow up to 19mm long. This species is a scavenger and can be found on dead fish or other animals (Marine Life of the North Atlantic by Andrew J. Martinez).

This species was found floating in the water column while scuba diving in Nahant. This species generally grows on solid substrate from sub littoral to forty feet. There is an isolated in population in Boothbay, Maine; but, the species is generally found from Cape Ann to New Jersey. It grows in large, rope-like, branching strands that are spongy and feel like wet felt. This species is dioecious and is green or yellow with light green tips. A fun fact is that this species was first seen in 1957 on Eastern Long Island then has continually spread along the coast. (Marine Life of the North Atlantic, Andrew J. Martinez)

Location: Lying on the dry high intertidal zone near the mud flats in East Boothbay.
Typical habitat: Low salinity, estuary, cold water environments globally, shallow intertidal buried in the soft mud or sandy sediment.
Characteristics: Elongate, oval clam shape, with one end slightly thinner than the other. Spoon-like chondropore off centered. Concentric growth rings, layered on the chalky white shell.
Fun fact: It can live without oxygen for several days, and dissolves the shell to buffer acidity when oxygen is low to deal with this stressor.

https://inverts.wallawalla.edu/Mollusca/Bivalvia/Myoida/Myidae/Mya_arenaria.html

Littorina littoria, more commonly known as the common periwinkle is an intertidal species native to the rocky coasts of the northeastern and introduced to the northwestern Atlantic ocean. This organism was found attached to a rock in the intertidal zone. Shell width for this species ranges from 10-12 mm and length 16-38 mm. Its color varies from grayish to grayish-brown and often has dark colored bands. A fun fact about this species is that it reproduces via internal fertilization of egg capsules.

References:
https://en.wikipedia.org/wiki/Common_periwinkle

Blidingia minima is found growing in tufts of carpet-like patches on rocks or wood, or epiphytic on other algae in the intertidal zone. The tubes are short and are attached by small discs. Cells are small and not highly visible under a microscope, which is a defining characteristic from a similar species, Ulva intestinalis. The thallus is frequently contorted and are yellowish green, belonging to the group of green algae.
Source:
Illustrated Key to the Seaweeds of New England by Martine Villalard-Bohnsack

Fun Fact:
Green algae are considered the group from which the higher plants evolved!
https://biologywise.com/green-algae-facts

Common Name: Sinistral Spiral Tube Worm

Location: Found on a washed up Fucus sp. at Canoe Beach, Nahant, MA.

Habitat: Found in the intertidal on algae, can also be found on hard substrates.

Physical Description: This tube worm grows coiling counterclockwise from its opening. White in color, and (1/8) inches in diameter.

Fun Fact: There is another species of tube worm like this one, but it grows clockwise from its opening instead.

Martinez, Andrew. Marine Life of the North Atlantic: Canada to Cape May. (New York: Aqua Quest Publications, 2003) 156-157.

Found on sand-covered rocks in the lower intertidal, it was originally from the Pacific, occurring in Japan, China, Korea and from Alaska to California. It has since invaded the northeast of the US. It is bushy with deep red-brown fronds, and can grow to 600mm long.

Source:
http://www.seaweed.ie/descriptions/Heterosiphonia_japonica.php

Location found: This False Irish Moss was found washed up on Canoe Beach, Nahant, MA.

Habitat types: It is found on the open coast in exposed areas, attached to rocks around the low-tide level and in mid- to lower intertidal pools.

Physical description: Rhodophyta. False Irish Moss is characterized by blade edges that are curled or rolled, with small, irregular, rounded or elongated proliferations or bumps. It has a firm thallus that allows it to grow 3-10cm tall. Color ranges from dark red to deep purple.

Fun fact: It is called False Irish Moss because it is often confused for Irish Moss, Chondrus crispus.

Villalard-Bohnsack, Martine. Illustrated Key to the Seaweeds of New England. Kingston: The Rhode Island Natural History Survey, 2003.

2 Invasive

Scientific Name: Carcinus maenas

Common Name: European Green Crab

Location Found: Intertidal zone at Canoe Beach in Nahant, MA

Habitat Types: under rocks in algae in intertidal and subtidal, can also be found in salt marshes (Pollock, L. W. (1998). A Practical Guide to the Marine Animals of Northeastern North America. New Brunswick, NJ: Rutgers University Press)

Physical Description: Has 5 teeth on either side of carapace; usually green but can be other colors (Martinez, A. J. (1994). Marine Life of the North Atlantic Canada to Cape May. Locust Valley, NY: Aqua Quest)

Fun Fact: Suspected to be introduced through water from shipping vessels in the early 1800s (http://www.aquaticnuisance.org/fact-sheets/european-green-crab)

1 Marine Invertebrate

Scientific Name: Asterias forbesi

Common Name: Forbes sea star

Location Found: Canoe Beach, Nahant, MA; 10-15 feet in subtidal

Habitat Types: found in the rocky and sandy subtidal zone along the Atlantic coast north of Cape Cod; is more common in this area than Asterias rubens

Physical Description: usually 5 arms; fairly rigid sea star even out of water; madreporite is orange; light tan in color (Martinez, A. J. (1994). Marine Life of the North Atlantic Canada to Cape May. Locust Valley, NY: Aqua Quest)

Fun Fact: they can regenerate limbs *see second photo with 7 arms (7 armed forbesi found 11/5 at Canoe Beach during night dive)