Preserved grass frogs for dissection and biology studies. This affordable and popular specimen is well-suited for the study of basic vertebrate anatomy and the pattern of organ systems. Presented as an intermediate between fish and mammals due to its semi-aquatic nature and also the presence in amphibians of a three-chambered heart. The circulatory system is thus incompletely divided into pulmonary and systemic circuits. Measurements from nose to cloaca. Sizes as indicated. Flinn-Preferred™ preserved specimens are safe, non-toxic alternatives to formaldehyde preparations. These specimens retain a more lifelike and natural appearance and have not been exposed to formaldehyde at any point. Look for the Flinn-Preferred™ symbol!