682 
SCIENCE. 
GENERA AND SpEcIES oF NoRTH AMERICAN FossiL 
VERTEBRATA IN THE GROUPS NAMED. 
FISHES. 
Group. Genera. 
Elasmobranchii............ 114 
Ichthyodorulites*.......... 34 
Aspidoganoideif............ 3 
lacod ermiiey steele le clevera/elstejaters 18 
MDT PN Ole yayeisiolelotaioleele/eielelelelsi=i° 10 
Crossopterygia............. 16 
Actinopteri. ../ccisie veieie)s)sielele 102 
Total of fishes...... goaug Pee 
BATRACHIANS. 
Group. Genera. 
Stegocephali................ 41 
Wmodlelarvrsterersiaione/crexeievotercter 2 
ATHTE oo obobDHOO Ud EHO OOO doo 2 val 
Total of batrachians...... 44 
% REPTILES. 
Group. Genera. 
Cotylosauria............... 12 
Chelydosauria.............. 2 
Anomodontia.............. 1 
Pelycosauria. ..-)3.0... 6 - ele, 
Testudines..... daopsoduooO 37 
Ichthyosauria.............. 5 
Plesiosauria......... p000000 14 
Rhynchocephalia........... 3 
PCELOSAULIAsreyeteleeretelereleneielstere 3 
Toricataf .....0....... dada,» Wz 
Squamatagwarietreteretaer ier 48 
Dinosauria ...... pdpoodsoos | WH) 
Total of reptiles.......... 219 
BIRDS. 
Genera, 59 ; species, 102. 
MAMMALS. 
Group. Genera. 
Protodontaryecicuseieiieiveetrclere 2 
IMMONDIE 5 SoccgbdH060 LOGO 13 
DD idelp plate allele evtoeieyet 21 
AB UGA atetaiclel tore iaieietotsvetaavors 16 
Sinemi airy chester iislevaseieietebele 5 
Cete..... dodoooucdotododos 42 
Species. 
537 
136 
Species. 
2 
41 
44 
*Mostly, at least, defensive spines of elasmo- 
branches. 
} This name, proposed by Dr. Gill, in 1876, ante- 
dates Cope’s Ostracodermi and Ostracophori. 
t Crocodiles and their allies. 
@ Mosasaurs, lizards and snakes. 
[N.S. Von. X. No. 254. 
Condylarthra........... soo 26 
Perissodactyla.............. 43 215 
Artiodactyla............ soo, (8) 207 
Ancylopoda................ 3 5 
Amblypoda............ oo IB 40 
Dinocerear.\. cree 5 33 
Proboscidea....... sfaeteverare 2 18 
Pillod ontias-m-vaieiy-tee eee 3 13 
Gilinesiycieyepyeteyeeyie okeietorere 40 99 
Insectivora..... dopooosacse 18 22 
Chiropbterarcerpitelsicierice ise 5 7 
Creodontalsjajer-iter-rsteiere <1 siete 39 103 
Carnivorancee cnc 55 134 
IPrimatesiesereiretsmtrrciciten 27 53 
Total of mammals........ 436 1182 
Foot-prints : Genera, 63 ; species, 147. 
Total of all groups: Genera, 1118 ; species, 3234. 
Of the classes of the list presented above, 
the birds are conspicuous because of the 
small number of species represented, the 
102 contrasting strongly with the approxi- 
mately 1100 species now inhabiting North 
America. It seems not unlikely that the 
habit possessed by birds of living in the 
open air and the tendency of their bodies 
to float for a long time after death have in- 
sured their destruction. Doubtless many 
of the smaller reptiles and mammals have 
been preserved because they met death in 
their burrows. A floating bird would be 
devoured by large fishes and reptiles. 
The list of the reptilesis a large one, the 
two largest orders being those of the turtles 
and the dinosaurs. The latter owe their 
preservation mainly to their great size. 
The turtles are likely to become buried in 
deposits, because they are mostly inhab- 
itants of the water, they readily sink when 
dead, and they are not easily devoured. 
The mammals present a formidable array. 
One-half of the groups in the list are ex- 
tinct, either wholly or from this continent. 
Those which have here living representa- 
tives show many more fossil than living 
species, excepting the bats, the rodents and 
the insectivores. The last two groups, be- 
ing composed mostly of small species, have 
