VISCEHAL ANATOMY OF THE CHARACIXID.E. 49 



Sngcmelil's conclusions appear to have been drawn in the main from the examination 

 of the following twelve species : — 



I 



Carnivorous True Characinids -j 



Macrodon trahira. 



Erythriuoids j Erythrinus unitceniatns. 



y Lebiasina bimaculata. 



Herbivorous True Characinids Citharhius Geoffroyi. 



( Alestes dent ex. 



Tetragonopterus fasciatus. 

 ,, melanurus. 



,, niaculatas. 



Anacyrtus gihbosus. 

 Hydrocyon Forskalii. 

 „ brevis. 



L Sarcodaces odoe. 



The Amioid characters insisted on so strongly in the paper in question, some only of 

 which I can claim to have verified, I Avill attempt to summarize. Tliey apply with 

 especial force to the Erythrinoids, hut some more generally. Most have reference to 

 the skull. They are as follows : — 



Tlie angle of inclination between the posterior face of the skull and the skull-roof. 

 The whole exterior form of the skull, its solid roof, its bony surface, its naked and 



sculptured hone, its lateral shielding by the extended suborbital bones. 

 The naked dentigerous palatines, and the almost identical formation of the border of 



the mouth. 

 Certain relations of the labyrinth and the recess in which it lies. 

 The relations of the suspensorium. 

 The presence of a median cartilage situated betAveen the hypopharyngcal bones, 



partially ossified and dentigerous in Ainia, rudimentary in Ei^ythrinKs, further 



reduced and fused in 3Iacroclon, absent in the other Characinidse and apparently 



in all other Teleosts. 

 The relations of the nasal bones with the premaxillte and the ethmoid. 

 The form of the parietals and of the squamosals. 

 The relations of the mucous canals of the cranial bones. 

 The relations of the intercalare. 



Certain relations of the occipital region of the skull and the associated nerves. 

 The development of a canal for insertion of the eye-muscles. 



In all these characters the conditions existing in at least some Characinidtie, usually 

 the Erythrinoids, are such, according to Sagemehl, as suggest a connection witli thosi; 

 found in Amla. The differences arc, indeed, often obviously such as have been con- 

 ditioned by the development in the foi-mer of the "Weberian apparatus. Nevertheless, 

 apart from the skull region, there appears to be but little in the comparative anatomy of 

 the two types to suggest close relationship ; and in the skull itself there is at least the 

 supraoccipital to be reckoned with as having no counterpart in Amia. 



In any case, the hypothesis of a direct genetic relationship between Amia and the 



8* 



