2G J\\r. C. T. Reirau on the 



the parasplienoid, the breadth of the ethmoid, no doubt 

 correhited with the strength of the praemaxillaries, and the 

 very small fontanel between the supra-occipital and parietals. 



Family 4. Electrophoridse ■'^. 



This family also contains only one species, the electric eel, 

 Electrophorus electricus {Gijmnotus electricus), differing from 

 tiie preceding in the characters of specialization enumerated 

 in the synopsis. 



Division 3. Cypriniformes. 



Body deep or moderately elongate ; dorsal and caudal fins 

 well developed ; pelvic fins usually present ; no adipose fin. 

 Mouth toothless, typically protractile. Opisthotic small or 

 absent ; posterior temporal fossa absent or variously deve- 

 loped, when present with a single posterior aperture. Lower 

 pharyngeals typically falciform, not opposed to the toothless 

 Tipper pharyngeals, but to paired posterior processes of the 

 basioccipital, which may unite below the aorta. Hyopalatine 

 and opercular bones all present ; palatine movably articulated 

 with mesopterygoid. Post-temporal simple. - 



Sagemehl (Morph. Jahrb. xvii. 1891, pp. 489-591, 

 pis. xxviii. & xxix.) has given a detailed account of the cranial 

 osteology of this group. The skeleton is very similar to that 

 of flie Characif'ormes, but there are some important differences. 



In all the Cypriniformes the orbitosphenoid joins the 

 alisi)henoids behind, the lateral ethmoids in front, the frontals 

 above, and the parasplienoid below. The palatine ends 

 behind in a convex head which fits a concavity of the meso- 

 pterygoid; internally it articulates with the " septo-max- 

 illaries," which are usually ossified and firmly united to the 

 vomer, appearing as antero-lateral apophyses of that bone, 

 but may remain as cartilages intervening between the vomer 

 and palatine. The " septo-maxillary " and palatine articu- 

 late anteriorly with the maxillary, either directly or through 

 the intervention of one or two pairs of " submaxillary " or 

 " pre-palatine " cartilages (Catostoraidse) or bones (Cobitidae, 

 Honudopteridse), which are more or less reduced in the 

 Cyprinid*. 



The prsemaxillaries have ascending pedicels which are 

 attached to the extremity of a movable " rostral ■"' bone; 

 this is articulated witli the vomer and is vertical when the 



* On the electric organ, see Saclip, * Uutersucliungeu am Zitteraal,' 



1881. 



