Geology and Natural History. 315 
: me 
Synopsis of the birds. In this part the author has given clear and 
closes the volume, which we heartily welcome as a very important 
addition to our educational works in Natural History. 
& 
"4 
i gement of the Families of Fishes, or Classes Pisces, 
Marsipobranchii, and Leptocurdii ; by _ 
pa Smithsonian Miscellaneous Collections.—This work consists, 
mong the so 
called fishes three distinct classes of vertebrates. These classes 
do not, however, correspond to those recognized by Professor 
Agassiz. he former unites the Selachians, Ganoids and Teleosts 
as sub-classes of the class Pisces; while the latter has proposed to 
consider them as distinct classes. The following are the higher 
divisions adopted by Professor Gill: 
lass Pisces, 
Series I.—Teleostomi or Branchiata. 
ub-class 1.—Teleostei, including 9 orders. 
Sub-class 2.—Ganoidei, including 6 orders. 
Series II.—Elasmobranchii. 
Sub-class 3.—Elasmobranchii, including 3 orders. 
Class Marsipobranchii. ; 
Orders Hyperoartii and Hyperotreti. 
Class Leptocardii. 
Order Cirrostomi. 
