212 University of Washington Publications in Biology [Vol. 2. 



Suprascapular, or supracleithrum. A bone lying between the post- 

 temporal and the cleithrum of the shoulder girdle. 



Supraorbital spine. The spine above the eye, between the preorbital 

 spine and the postorbital spine. If only two spines are present, 

 the supraorbital is absent in Sebastodes. 



Supraoral teeth. Teeth on the supraoral plate or lamina of lampreys. 



Suspensorium. The chain of bones from hyomandibular to the pala- 

 tines. 



Suspensory bones. Bones by which lower jaw is fastened to the skull. 



Suture. Line of union of two ossified bones. 



Symphysis. Point of junction of the two parts of lower jaw; tip of 



chin. 

 Symplectic. The bone that keys together the hyomandibular and 



quadrate posteriorly, in fishes. 



Synonymy. A list of technical names applied to a certain genus or 



species. 

 Swim bladder. See air bladder. 



Tail. The part of the body posterior to the body cavity ; in fishes ap- 

 lied to the caudal fin only. 



Teeth bifid or bicuspid. With two projections. 



Teeth deciduous. Said of teeth which are shed. On certain fishes the 

 teeth are shed during spawning season. Certain pharyngeal teeth 

 are attached by flesh or cartilage to the pharyngeal bone and 

 are called deciduous although they may replace the normal teeth 

 when the latter are lost. 



Teeth lateral. Said of the series of teeth on each side of the oesopha- 

 geal opening of lampreys. 



Teeth midticuspid. Many cusps or projections on the teeth. 



Teeth supraoral. See supraoral teeth. 



Terete. Cylindrical and tapering. 



Terminal. At the end. 



Tessellated. Marked with little checks or squares, like mosaic work. 



Thoracic. Pertaining to the thorax or chest ; ventral fins are thoracic 

 when attached immediately below the pectorals, the bones being 

 attached to the shoulder girdle. 



Transverse. Crosswise. 



Transverse processes of vertebrae. Lateral processes of the verte- 

 brae (abdominal) to which the ribs are attached. 



Trenchant. Compressed to a sharp edge. 

 Truncate. Abrupt, as if cut squarely off. 

 Tubercle. A small excresence, like a pimple. 



