446 REPORT OF NEW JERSEY STATE MUSEUM. 
Opercular bones. Membrane bones on side of head. 
Opercular fiap. Prolonged upper angle of opercle, as in sunfishes. 
Opisthocelian. Concave behind only, usually referring to  ball-and-socket 
jointed vertebre. : 
Opisthotic. Bone of skull to which lower limb of post-temporal usually 
articulates. 
Orbicular. Nearly circular. 
Orbit. Eye socket. 
Ossicula audtius. Ear-bones. 
Osteology. Study of bones. 
Oviparous. Producing eggs developed after exclusion from the body, as in 
most fishes. . 
Ovoviviparous. Producing eggs hatched before exclusion from the body, as 
in the dog-sharks. 
Ovum. Egg. 
Palate. Roof of mouth. 
Palatines. A pair of membrane bones on roof of mouth, one on each side 
extending out the band from vomer. 
Palustrine. Living in swamps. 
Papilla. A small fleshy projection. 
Parapophyses. lateral processes on some abdominal vertebre to support 
ribs. 
Parasphenoid. Bone on roof of mouth following vomer. 
Parietal. Bone on side of head above. 
Parotic process. Formed on side, back on the skull, by the pterotic and 
opisthotic. 
Pectinate. ‘Toothed like a comb. 
Pectoral. Relating to the breast. 
Pectoral fins. Front or upper paired fins corresponding to front limbs of 
other vertebrates. 
Pelagic. Living on or in high seas. 
Pelvic girdle. Bones supporting ventral fins. 
‘Pelvis. Bones to which hind limbs, or ventral fins, are attached. 
Peritoneum. Membrane lining abdominal cavity. 
Pharyngeal bones. Bones behind gills at beginning of cesophagus, of various 
forms, usually with teeth. Placed usually as a single pair below and 
a double pair above. 
Pharyngobranchials. Upper elements of branchial arches, usually bearing 
teeth. 
Pharyngognathous. Having lower pharyngeal bones united. 
Physoclistous. Waving air-bladder closed. 
Physostomous. Having air-bladder connected by a tube with alimentary 
canal. 
Pigment. Coloring matter. 
Pineal body. A small ganglion in the brain, a rudiment of an optic lobe 
connected with a third or median eye. 
Pineal eye. Pineal body. 
Pituitary body. A small ganglion in the brain. 
