110 



of the connective tissue which line the floor of the branchial cavity." This foramen has 

 not been reported from other cyprinids. 



In Phoxinus, the quadrate is high and short. The posteroventral side of the process, arti- 

 culating with the symplectic, bears a notch in P. cumberlandensis (TS 129[1]), which is 

 absent in other species of Phoxinus and in the outgroups (TS 129[0]). 

 Symplectic (Figs.67A-D, 68A-D). In cyprinids, the symplectic is an elongated rod- 

 shaped bone and positioned ventral to the metapterygoid. The symplectic articulates with 

 ventral margin of the metapterygoid dorsally, dorsal margin of the posterior process of 

 quadrate ventrally, and ventral side of the hyomandibular posteriorly. 

 In Phoxinus, the shape and the articulation of the symplectic with other bones are simi- 

 lar to that in most cyprinids. In P. eos, oreas, and tennesseensis, the symplectic is much 

 slender (TS 1 30[ 1 ] ) than that in other species of Phoxinus and in the outgroups (TS130[0]). 

 Metapterygoid (Figs.67A-D, 68A-D). In cyprinids, the metapterygoid is a plate-like en- 

 dochondral bone located anteriorly to the hyomandibula. It articulates with the ventroan- 

 terior margin of hyomandibula posteriorly, dorsal margin of the symplectic ventrally, 

 posterior margin of endopterygoid and posterior margin of the quadrate anteriorly. 

 In Phoxinus, the metapterygoid is irregular in shape with two articular facets for the hy- 

 omandibula (Figs.67A-D, 68A-D). The dorsal margin of the metapterygoid bears a pro- 

 cessus basalis (basal process) on its anterior portion, a processus metapterygoideus lateralis 

 (lateral process) on its posterior portion, and a notch between the two processes. The tri- 



