A LIST OF THE GENERA AND FAMILIES OF MAMMALS. 41 
as bona fide genera of mammals; and (b) those given to forms referred 
to the class Mammalia through error. As examples of the last kind 
may be mentioned the reptilian genera Brithopus, Aladeisteriodon, 
and Orthopus, and the fish genus Wa//ago, which were inadvertently 
listed as mammals in the Nomenclators of Agassiz and Scudder. 
These names have not been admitted in the body of the index. Those 
belonging to forms described as mammals, however, are listed in their 
proper places with references to the explanations as to their true posi- 
tion. Altogether a score of such names must be rejected or rather 
transferred to other groups. As shown by the following list, nearly 
all of these names belong to reptiles, although two extinct birds of 
southern Patagonia were originally described as mammals, and one 
genus (Chirotherium) was doubtfully referred to the Mammalia or the 
Amphibia. Three genera—Caryoderma Cope, Tritylodon Owen, and 
Theriodesmus Seeley—have been considered mammals until very 
recently. The Mesozoic genera Theriodesmus and Tritylodon, 
although considered as representatives of the earliest ancestors of the 
Mammalia, have long been known to possess reptilian characters, and 
are now regarded as true reptiles. 
List of Genera referred to Mammalia but now known to belong to other Classes. 


| 





Name, authority, and date. Locality. Present class. | 
Brithopus Kutorga, 18384 .............. RUSS Deo ase te ad EN C MEME Reptilia. 
Caryoderma Cope, 1886 ...-............. NOorthern|Kansas--------5------.- Reptilia. 
Chirotherium Kaup, 1885 ............... Saxe-Meiningen, Germany....... | Amphibia? 
Ischyrotheriwm Leidy, 1856 ............. I"South'Dakota:------2- 22252-55522 | Reptilia. 
"«:KüaederstenodornspueningeretstGasc | eise cee nee EIC Reptilia. 
Orthopus Kutorga, 1888a .............. USS Mise e crow eee rri eere | Reptilia. 
:Prmmraaciussligensietpe scm S s/s Aad DVN sees paceoe sees eee cee eco | Reptilia. 
Phorusrhacos Ameghino, 1887 .......... Southern Patagonia .............. Aves. 
"IPelychlmpidessMaedonald;s864x-c oen aedes US sse See Tunicata. 
Polyptychodon Emmons ................ NorthiCaroling sess eeeee eee | Reptilia. 
Psephophorus Meyer, 1847 .............. Neudorf; Hungary sss. asso. | Reptilia. | 
IDterotnenumpEischenelsldte e Roan Sete ceocosse Bs STORE Reptilia. | 
Rhinoceroides Featherstonhaugh, 1831..| Somerset County, Pennsylvania .| Fragment of rock. | 
Theriodesmus Seeley, 1887 .............. | Fraserburg, Cape Colony......... | Reptilia. 
Thylacodes Roger, 1894a ............... White Horse Plains, Australia ...| Mollusea. | 
.Tolmodus Ameghino, 1891 ............. Southern Patagonia.............. Aves. | 
Tritylodon Owen, 1884. ................. Orange Free State, Africa ........ Reptilia. 
Tropodon Rafinesque, 1832 ............. Somerset County, Pennsylvania..| New name _ for 
Rhinoceroides. 
WWaagosBleeker 15580 e so aes A dos etecccigerst eae tA SEE EE Pisces. 


ETYMOLOGY OF NAMES. 
It is generally admitted that a name need not mean anything, and 
that in any case its meaning is of very slight importance from the 
standpoint of the systematic zoologist. According to the A. O. U. 
Code of Nomenclature, **a name is only a name, having no meaning 
