Pennak's Freshwater Invertebrates of the United States: Porifera to Crustacea, 4th Edition

Rating:
Summary: A great book with keys that work!
Review: This is an excellent book that belongs on the self of anyone who wants to be considered up-to-speed on the critters that dwell in our waters. I've had the opportunity to use the annelid and the tardigrade keys thus far, and both worked wonderfully. The general information for all of the groups is well written and up-to-date, and the addition of color plates is a nice touch. Highly recommended!