"Guide to Benthic Invertebrates observed from Hudson River Park Sanctuary Waters," was prepared by Anne Gallagher, US Geological Survey

The guide, complete with colored photos can be viewed as a PDF

To translate that mouthful of a title: "Benthic" means at the bottom of a body of water.

"Invertebrate" means an animal without a backbone; Invertebrates represent some 95% percent of animal species!

Typical, local waterways invertebrates are worms, clams, snails, crustaceans and tunicates!

Crustaceans are critters such as crabs, lobsters, barnacles and shrimp.

Tunicates are like living balloons with two openings. A tunicate is a rubbery sack with two siphons to draw water into and out of the body. If you touch them, they squirt which gives them one of their names "sea squirts."