scallops

The bivalve seashells, or shells that come in two parts or halves, can be similar in appearance, but not all bivalves are “clams”. I’m not scientifically minded, but I’ve been learning the difference between the shells I collect and photograph.

I’ve gathered some photos of the more common bivalves I see on beaches and in the saltwater rivers around my area of Florida. A general bivalve list includes: clams, oysters, scallops, cockles and mussels.

Clams and Arks

My photos below in this section contain various types of clam shells. Also, there are many types of Venus clams and loads of coquina clams. Shells called “arks” are also clams.

quahog clam living alive hefty shell — Tagelus clam shell

ark shell with brown stripes — Ponderous Ark

broad ribbed cardita shell underneath — The broad ribbed cardita, measures about an inch in length.

broad ribbed cardita bivalve seashell — The broad ribbed cardita, measures about an inch in length.

Oysters

I rarely collect oyster shells but we see oyster beds while out on our boat. Oyster shells are sharp, and are the scourge of boaters because they can slice up the underside if a bed is accidentally hit while running. While walking the flats in oyster areas I can hear the shells snapping as they feed.

oysters attached to tree roots — Oyster Shells

Scallops

Scallop shells can be some of the prettiest shells. Certain types of scallops have one flat side and the other is normal / rounded. The concave part is in the sand or bottom and the flat part is on top and opens like a flap when the scallop is alive. Scallops propel themselves around by opening and closing their shells.

The Kitten Paw and larger Lion’s Paw shells are also scallops. I found these Kitten Paw shells while visiting Sanibel Island on the Gulf coast. I’ve never seen any where I live on the east coast.

Types of scallop shells — 2 inches across

kitten paw seashells — Kitten’s Paw Scallop Shells

Cockles

Cockles are not clams although they look similar. Because they have an oval shape with high top part (umbo), when a whole cockle is viewed from the side it resembles a heart. For that reason, they are known as the heart shell or heart cockle.

bivalve cockle shells — Atlantic Giant Cockle Shell

inside the giant cockle shell — Atlantic Giant Cockle Shell

Mussels

Mussel shells are something I rarely collect or photograph because they really are not great looking shells. They are dark colored and shaped like thin fans. The pen shell is distantly related and I have a few pictures here. The pen shell can be nearly a foot in length and is more impressive than a mussel.

mussel seashell — Open and empty mussel shell

part of a pen shell on the beach sand — Pen shell next to my son’s foot

shells found at beach — Pen shell next to my son’s foot

Keep Reading! … Newest Posts on This Blog

03/08/2026Tent Camping in Florida

If you like to camp in a tent in Florida, we've seen …

02/22/2026Please Accept My Apology

I apologize for the bad way my blog is behaving. I am …

One of my favorite seafoods is scallops. I never used to think much about their shell, until I began to find them along the beach.

The scallop is rounded in shape with protruding flaps at the hinge area (they are bivalves). Sometimes the flaps are similar in size and sometimes one is much larger than the other (Scaly Scallop). Sometimes they are worn and barely visible. Ridges fan out from that front point and can be thin, wide (Lion’s Paw), rough (Rough Scallop), or flat (upper part of the Zig Zag and Rough Ribbed scallops). Sometimes each half of the shell can look entirely different.

Here in Florida there are a few varieties of scallops. Probably the most common type is the Atlantic Calico Scallop (Argopecten gibbus). Shells are colorful in shades of pink and purple with other possible colors like yellow and orange. The entire shell can be colored, or it may have splotches or patterns of color over the shell. This type is what I find on the East coast where I beach-comb. Size is usually around 1-2 inches.

One of the most unique looking scallop is the Kitten’s Paw (Plicatula gibbosa). It’s a tiny shell which is a bit thick and bumpy with more irregular ridges. The ones I have collected came from the Sanibel Island area. They are off-white with orange, or sometimes yellow, coloring with cross-hatch type markings. I have never found one on the East coast of Florida where I live, but my reference book claims this scallop lives all around the state.

The Atlantic Calico Scallop (Argopecten gibbus) is probably the most commonly found scallop shell in Florida. I’ve collected them on the west coast and east.

The brightly colored calico scallop shells in my photos above were collected on the West / Gulf coast of Florida. In comparison, the shells in my photo below (Calico shells only) were collected on the East coast. Shells in the Gulf area tend to be more well preserved as they are not churned up in the waves like on the Atlantic side.

The black scallop shell was collected from the Ponce Inlet area. I’ve written a post about black shells, because black is not the normal color for seashells.

If you’d like a free, printable coloring page which features the scallop seashell, click here.

Links to Other Types of Scallops Mentioned Here

Atlantic bay scallops (Argopecten irradians) – can be larger than the calico and will reach 4 inches across. They are less colorful than calico also, and will be white, orange or grayish brown. These used to be very common all around Florida and now are not.
Scaly scallops (Caribachlamys sentis) – are small (1.6 inches) and more pointed. Their outstanding characteristic is that one of the front flaps is very large. (The link also shows other types of scallops which I mention in this post.)
Zigzag scallops (Euvola ziczac) – are flat shells (top valve) with colorful zig-zagging colors of purple, pink or orange. They can be up to 4 inches wide. The bottom part of the shell is rounded like a regular shell. (See a good photo in that link.)
Round-rib scallops – look similar to the Zigzag and also flat, but their ribs are wider. They are smaller than the Zigzag at max 2 inches.
Rough scallops – This type is rarely found on beaches. Usually they are solid colored and only grow to 1.5 inches. They have rough ribs, with tiny bumps, hence the name.
The coveted Lion’s Paw is a scallop shell with extra wide ridges. It is not commonly found anywhere here in Florida, but it is possible to find one. Your best chance of finding a Lion’s Paw would probably be over by Sanibel Island on the Gulf.