440 Recent Literature. [June, 
new characters. He throws much light on their systematic 
position, especially in demonstrating the differences which dis- 
tinguish them from the Dafedide, and their near affinity to 
Paleoniscide. Indeed the author scarcely adduces sufficient 
ground for their separation as a family from the latter. 
Two of the important characters on which he lays most stress, 
viz., the non-coincidence of the median fin-rays with’ their inter- 
neural and interhæmal bones, and the absence of suboperculum, 
undoubtedly remove the fishes which possess them, from the order 
Lsospondyli, where the present writer formerly placed them. The 
degree of ossification of the cranial and vertebral bones, is of less 
importance. Dr, Traquair places this family and its allies in 
the Chondrostei (which he calls Accipenseridi) with <Accipen- 
seridæ, etc. But he does inform us as to the structure of the 
articulations of the pectoral and ventral fins; perhaps his material 
does not permit it. A comprehension of this part of the skeleton, 
is, in the present writer’s estimation, necessary to the determina- 
tion of the position of any fish in the system. The Chondrostet 
form a group, intermediate between the Crossopterygia and other 
fishes (or Actinopteri)! having the ventral fin of the former, and 
the pectoral of the latter. From all the evidence yet advanced, 
the ventral fins of this group appear to be those of the tribe 
Actinopteri, with which they should probably be associated. In 
this group they will occupy the lowest position, below the Ging- 
lymodi (Lepidosteide, etc.), differing from all the fishes which 
compose the former, in the primitive character of the fin-rays 
already mentioned. They will form a distinct group of the same 
rank as those I have called orders, to which the name of Lysoptert 
may be given. The definition will be, actinopterous fishes with the 
median fin-rays not joined to the interhemal and interneural bones, 
and not coinciding with them in number ; and without subopercu- 
um. 
Dr. Traquair shows the entire insufficiency of Prof. Young’s 
system of palzozic fishes, but seems not to be sure but that Zegt- 
dosteus has some relatives from below the upper cretaceous forma- 
tions. He writes ganoids, with a capital G, as though it were a 
natural group. Certainly the arguments adduced by the support- 
ers of this division (e. g. Dr. Lütken), as well as by its opponents, 
show that it does not conform to Dr. Traquair’s definition of a 
true division (p. 386); “ What we require is that the assemblage 
of characters shall be exclusive.” 
The characters adduced by Dr. Traquair, appear to confirm the 
writer’s reference of the Dapediide to the /sospondyli.—E. D. (ae 
WE HAVE SELDOM MET with a case of more unblushing 
piracy than lies before us in “Rand, McNally & Co.’s Geologica’ 
and Mineralogical Map of Colorado, copyright secured 1879. 
1 Proceed. Amer. Ass. Ady. Sci. 1878. 293. 
