The Chalder (physiological classification AUGL) are a sapient aquatic species that hails from planet Chalderescol II. They vaguely resemble a forty-foot long crocodile, although with flippers instead of legs and gills instead of lungs. Chalders possess a long muscular tail which seems to be their main organ of defense. They spend their whole lives in the warm greenish waters of their home planet, or in tanks containing a similar environment when in space. Their fins are described as stubby and arranged in an apparently haphazard manner and they also possess a frill of ribbon-like tentacles encircling their middle. The Chalder body is protected by heavy plates and scales which form a true exoskeleton. Despite having six rows of teeth, these creatures appear to be herbivorous since their tanks' floors are covered with spongy blue flora used as both food and decoration.
- Sector General by James White
- Visitor at Large by James White
- Major Operation by James White