368 Dr. W. G. Kiaewood on lite 



maxilla as well as the prcmaxilla, and the absence of the 

 lower hypohyal : none of these features arc exhibited by 

 Gonorhyncl.ns. 



The Paiulodontidre are more nearly allied to the Osteo- 

 glossid?e than to any other family of Teleostean fishes, and 

 resemble them in the presence of a paired peg of the para- 

 sphenoid for articulation with the entopterygoid, in the large 

 size of the nasal bones and their incorporation into the 

 cranium, and in tlic meeting of the parietal bones. In those 

 characters ia which Fantodou differs from the Osteoglossidie 

 — such, for instance, as the absence of the intcropcrcnlar 

 and the fusion of the two premaxillary bones — it does not 

 approach the Gonorhynchidae. 



Phractolctmiis, the sole genus of the family Phractohcmida?, 

 has a remarkably aberrant skull, only a few features of 

 which can be found to recur in the skull of Gonurhijuchus. 

 Such are the failure of the first basibranchial to ossify, the 

 small size of the mouth, the reduction of the dentition, and 

 the forward position of the corouoid process. Of these 

 features the first occurs in genera as remotely allied as 

 Heterotis, Notopterus, and Cromeria, although not occurring 

 in Osteoglossum and Arapabna, with which Heterotis has 

 obvious relations. The second and third characters are such 

 as have clearly been evolved independently in a numl)cr of 

 groups of fishes, while the last appears to be connected with 

 the reduction in the size of the mouth, and is met with (to a 

 slighter extent) in such unrelated genera as Leptolepis, Labeo, 

 and Chato'es.sus. 



Notopterus, as above mentioned, is a form which has a 

 cartilaginous first basibranchial — the feature is so unaccount- 

 able that one seizes upon it as possibly affording a clue to 

 the elucidation of the question of affinity. But the sugges- 

 tion of close relationship between Gonorhynchus and Noto- 

 pterus is not sustained by a closer examination of the cranial 

 characters, for Notopterus has the right and left parietal 

 bones meeting in the median line, an orbitosphenoid traversed 

 by the cranial cavity, a lateral cranial foramen, an air- 

 containing vesicle at the side of the occipital region of the 

 cranium, teeth on the parasphenoid, a gape bounded above 

 by both prcmaxilla and maxilla, no subopercular bone, 

 tendon-bones projecting downward from the posterior end of 

 the second basibranchial, a single hypohyal on each side — 

 characters which collectively dissociate this genus from 

 Gonorhynchus. 



The Morniyridse arc a sharply marked family whose 



