CXXXV1 FISHES OF ILLINOIS 



Pterygoids. Paired bones of the roof of the mouth. (See entopterygoid and ectopterygoid.) 



Pu&ic bones. (See pelvic girdle.) 



Punctulate. Dotted. 



Pyloric caeca. (See caecum.) 



Quadrate. One of the chain of bones connecting the lower jaw with the skull. 



Ray. An articulated cartilaginous rod supporting the membrane of a fin. (Fig. 1, d2r. See 



spine.) 



Retrorse. Turned backward. 

 Rudimentary. Undeveloped. 

 Scapular arch. (See shoulder girdle.) 

 Scute. A bony or horny plate. 

 Shoulder girdle. The framework of bones, in most fishes connected with the skull, to which 



the pectoral fins are attached, including the post-temporal, clavicle, postclavicle, hyper- 



coracoid, and hypocoracoid. 

 Soft dorsal. That dorsal fin or portion of it which consists of soft rays only. (Fig. 1, d2r. See 



spinous dorsal.) 

 Spine. Fin rays which are unbranched and unarticulated, and, as a rule, more or less stiffened 



and sharpened apically. (Fig. 1, d2s. See ray.) 

 Spinous dorsal. The dorsal fin or portion of it which consists of unbranched, unarticulated 



spines only. (Fig. 1, d2s. See soft dorsal.) 

 Spiracle. An opening in the head, anterior to and above the opercular opening, representing a 



primitive gill-cleft, in paddle-fishes and in some sturgeons. 

 Spiral valve. A spiral infolding of the wall of the intestine in ganoid fishes. 

 Subopercle. The bone below the opercle. (Fig. 1, so.) 

 Suborbitals. (See infraorbitals.) 

 Subulate. Awl-shaped. 



Supplemental maxillary. A small bone lying on the upper posterior edge of the maxillary. 

 Supraoccipital. The unpaired bone at the back of the skull, usually with a crest above. 

 Supraoral. Above the mouth. 



Symphysis. The point of junction of the two parts of the lower jaw in front; the tip of the chin. 

 Symplectic. A bone connecting the hyomandibular and quadrate. 

 Swim-bladder. (See air-bladder.) 

 Teleost. A name applied to fishes which have the skeleton fully ossified, embracing most recent 



forms. (See ganoid.) 

 Terete. Cylindrical and tapering. 



Tessellated. Marked with checks or squares, as in mosaic work. 

 Thoracic. Pertaining to the chest or thorax. 

 Thoracic ventral fins. Ventral fins which are attached far forward, neajify beneath the pectorals, 



the pelvic bones being connected with the shoulder girdle. (See key to families, bb, note, 



p. 2.) 



Truncate. Cut squarely off. 



Vent. The external opening of the alimentary canal; anus. 

 Ventral. Pertaining to the abdomen. 

 Ventral fins. The posterior or lower paired fins, corresponding to the posterior limbs in higher 



vertebrates. (Fig. 1, v.) 

 Vertebra. A single bone of the spinal column. 



Vertical fins. The fins (dorsal, anal, and caudal) on the median line of the body, in contradis- 

 tinction from the paired fins (pectorals and ventrajs) . 

 VUliform. Of the form of villi. Said of teeth which are slender and crowded closely together 



in velvety bands. 



Vomer. The anterior bone of the roof of the mouth. (Fig. 56, vo.) 

 Weberian ossicles. A chain of small bones developed in connection with the modified anterior 



vertebra! and connecting the air-bladder with the ear in suckers, carps, and catfishes. 



