374 



TELEOSTEI 



Cyprinidae. Often there are spinous serrated anterior dermal rays 

 on the median and paired fins ; such spines are formed by the 

 enlargement and ankylosis of the segments of the lepidotrichia 

 from the base outwards, unfused segments frequently remaining at 

 the tip. In the pectoral girdle, besides the mesocoracoid arch, must 

 be noticed the great development of the coracoids, which often meet 

 in a ventral suture (Fig. 365). The Cypriniformes have diverged 

 in two chief branches : the Characinidae depart least from the 

 primitive type, and lead to the Cyprinidae and eel-like Gymnotidae ; 

 the other branch includes the Siluroidei, among which are some of 

 the most specialised of Teleosts. 



pmx 



.pro. 



TRIBE A. CHARACINOIDEI. 



This includes the more generalised forms, with parietals distinct and 

 not separated by the supraoccipital, well-developed opercular bones, three 



to five branchiostegals, 



A- , and a symplectic. Ex- 



cept on the first four 

 segments', the anterior 

 parapophyses are usu- 

 ally short, separate from 

 the centrum, and bear- 

 ing pleural ribs. The 

 second and third centra 

 become fused and the 

 parapophyses of the 

 fourth vertebra en- 

 larged, bent downwards, 

 and applied to the air- 

 bladder, which is gener- 

 ally subdivided into an 

 anterior and a posterior 

 chamber (Fig. 199). 

 From the latter comes 

 the pneumatic duct. 

 Epipleurals and epi- 

 neurals are present. 



Family CHARACINI- 

 DAE. The scales are 

 cycloid or with a hinder 

 ctenoid edge. The max- 

 illa may be toothed as 

 well as the premaxilla 

 and dentary ; the teeth 

 may be powerful and 



(Fig. 360). Sometimes an incomplete interorbital 

 The anterior chamber of the air-bladder may be 



-pro. 



FIG. 360. 



Left jaw-bones of A, Erythrinus unitaeniatits, Spix. ; and 

 B, Cithariniis Geoffroyi, Cuv. (After Sagemehl.) an, angular ; 

 art, articular ; </, dentary ; ect, ectopterygoid ; cut, entoptery- 

 goid ; /, foramen ; hm, hyomandibular ; mt, metapterygoid ; 

 mx, maxilla ; pi, palatine ; pmx, premaxilla ; pro, preopercular ; 

 q, quadrate ; s, cartilage ; sy, symplectic. 



with several cusps 

 septum is present. 



