Dec. 28, 1916. Fishes of Panama — Meek and Hildebrand. 373 



Ocellus. An eye-like spot; a dark spot with a lighter border. 

 Opercle. The thin flat bone on sides of head covering the gills; also 



called gill-covers. 

 Orbit. Eye socket. 

 Osseous, Bony. 

 Oviparous. Reproducing by means of eggs laid and hatched outside 



of the body. 

 Ovum (plural ovi). Egg. 

 Palate. The roof of the mouth. 

 Palatines. Bones of the roof of the mouth, one on each side of the 



vomer, often provided with teeth. 

 Papilla. A small fleshy projection. 

 Papillose. Covered with papillae. 

 Parietal. Bone of the side of the head. 

 Pectinate. Having teeth like a comb. 

 Pectoral. Pertaining to the breast. 

 Pectoral fins. The anterior or uppermost paired fins, corresponding to 



the anterior limbs of the higher vertebrates. 

 Peritoneum. The membrane lining the abdominal cavity. 

 Pharyngeal bones. Bones behind the gills and at the beginning of the 



oesophagus, usually provided with teeth. 

 Plicate. Folded; showing folds or wrinkles. 

 Plumbeous. Lead colored; dull bluish gray. 

 Postorbital. Behind the eye. 

 Premaxillaries. The bones, one on each side, forming the front of the 



upper jaw, usually bearing most of the upper teeth. 

 Preopercle. A thin bone lying just in front of the opercle. 

 Preorbital. The bone lying just in front of the eyes. 

 Protractile. Capable of being drawn forward. 



Pseudobranchiae. Small gills developed on the inner side of the opercle. 

 Punctate. Dotted with fine points. 

 Ray. One of the bony or cartilaginous supports of a fin. Rays are 



either spiny or soft, the latter are either simple or branched. 

 Recurved. Turned backward or toward the point of origin. 

 Reticulate. Marked with a net work of lines. 

 Retrorse. Turned backward. 

 Rudimentary. Undeveloped. 

 Rugose. Rough, wrinkled. 

 Scute. An external horny or bony plate. 

 Serrate. Notched like the edge of a saw. 

 Setiform. Having the form of a bristle. 

 Snout. That portion of the head which projects beyond the eyes. 



