93 



the ventral side of the dorsal portion and the dorsal side of the pharyngeal process. The 

 posterior process was formed by the haemal arches of the third vertebral segment assi- 

 milated into the skull; the centrum of the vertebral segment was united by the basiocci- 

 pital to form the condyle (Ramaswami 1955a). 



The basic morphology of the basioccipital in Phoxinus is similar to that in other cypri- 

 nids described above. Variations among the species of Phoxinus include the following as- 

 pects. 



In P. oreas, neogaeus, and phoxinus, a notch is present on the middle of the anterior mar- 

 gin of the basioccipital (TS 89[1]); the notch is absent on the anterior margin in other spe- 

 cies of Phoxinus (TS 89[0]). In all Phoxinus species, a shallow and elongated concavity 

 is present at the anteromiddle portion of the ventral side of the dorsal portion (of the ba- 

 sioccipital) on which the parasphenoid overlaps. In P. neogaeus, phoxinus, brachyurus, 

 and issykkulensis, the concavity is triangular and extends to the anterior half of the dor- 

 sal portion (TS 90[1]). In other species of Phoxinus, however, the concavity is rectangu- 

 lar and extends to the posterior half of the dorsal portion of the basioccipital (TS 90[0]). 



Fig. 55: Basioccipital of Pho- 

 xinus (a: ventral view; b: dor- 

 sal view). A: P. erythrogaster 

 (KU 5773, 51.5 mm SL); B: 

 P. oreas (KU 3259, 55.0 mm 

 SL); C: P. cumberlandensis 

 (KU 18934. 52.0 mm SL): D: 

 P. eos (KU 12255. 43.0 mm 

 SL). Scale bars = 1 mm. 



