The book has no illustrations or index. It may have numerous typos or missing text. However, purchasers can download a free scanned copy of the original rare book from the publisher's website (GeneralBooksClub.com). You can also preview excerpts of the book there. Purchasers are also entitled to a free trial membership in the General Books Club where they can select from more than a million books without charge. Subtitle: With Introductory Notes Upon the Hydrography of the Illinois River and Its Basin; Part Ii, Constituent Organisms and Their Seasonal Distribution; Original Publisher: Illinois State Laboratory of Natural History; Publication date: 1908; Subjects: Plankton; Education / Teaching Methods