1892.] Geology and Paleontology. 941 
taining one class each, and Craniata, subdivided into five classes, viz. : 
Agnatha, Pisces, Batrachia, Monocondylia, and Mammalia. 
The greatest changes in classification, as a consequence of the latest 
accessions to the knowledge of the subject, will be found in the Pisces, 
In classification the definite characters are brought into prominence 
and analytical keys are adopted as the most perspicuous method of 
exhibiting them. 
Carefully prepared charts give aecurate ideas as to the geological 
range of the different orders, and of the time relations of these to each 
other. 
The books are profusely illustrated with cuts and drawings, many 
of which represent American material. 
Crook on Saurodontide from Kansas.’—In this paper the 
author gives anatomical descriptions of some species of Portheus and 
Ichthyodectes from the Niobrara chalk of Kansas, and makes some 
comments on the systematic position of the Saurodontide and of the 
Erisichtheide. The anatomical work is good, and some needed rectifi- 
cations of original descriptions are made. We find it necessary, 
however, to make some comments on the systematic part of the work, 
in which are to be found numerous oversights. 
In the first place the author has not observed that I have on several 
occasions published the fact that the name Daptinus Cope is a syn- 
onym of Saurodon Lea, which was proposed many years previously. 
It was from this genus that I gave the family the name first proposed, 
of Saurodontide. The fact that Prof. Zittel many years later gave 
this name to a very distinct family does not authorize the giving of a 
new name to the family first so called by me, as is done by Mr. Crook. 
It only signifies that another name should be used for Prof. Zittel’s 
family, as I have proposed in THE American NATURALIST, 1889, p. 
858 (Macrosemiide). The statement that my original Saurodontide _ 
embraced a genus which does not pertain to it should be supplemented 
by the information that I removed this genus (Erisichthe) from it, and 
established a new family for it (Erisichtheids), only two years later 
than the date of the publication of my volume on the Cretaceous Ver- 
tebrata. In the next year I made the Erisichtheide the type of a 
new order, the Actinochiri,‘ adopting, however, the name Pelecopter- 
2Ueber einige fossile Knochenfische aus der Mittleren Kreide von Kansas; von 
Alja Robinson Crook. Palaeontographica, Vol. xxxix. 1892, p. 107. 
3Bulletin U. S. Geolog. Survey Ter., 1877, iii, p. 822. 
4Proceeds. Amer. Asso. Adv. Science, 1878, p. 299. 
