180 Reviews—Prof. K. v. Zittel’s Palichthyology. 
cerci”’ had been given i uniform terms, side by side, we venture to 
think that the illogical nature of their separation would have become 
apparent. The Chondrostei are said to be destitute of scales and 
branchiostegal rays, while the Heterocerci are characterized by both 
these structures well developed ; and these are the sole differences 
of importance recorded. Nevertheless, Chondrosteus is termed a 
Chondrostean, while the fact is omitted that its numerous large 
branchiostegal rays were described and figured by Egerton thirty 
years ago; and one of the Chondrosteans mentioned (Crossopholis) 
has the flank-scales even more developed than those of an admitted 
member of the Paleoniscidse, Phanerosteon. Under such circum- 
stances, Dr. v. Zittel’s proposed rearrangement is far from being an 
emendation of Dr. Traquair’s results, and must be regarded as a 
decidedly retrograde step. 
On reaching the Order ‘ Lepidosteide,” the influence of the 
author’s own researches soon becomes apparent; the Paleontological 
Museum of Munich containing so large a series of fine Lepidosteoids 
from the Bavarian Lithographic Stone. Several rearrangements of 
species are proposed, with one or two new genera; and there are 
many original figures, drawn from actual specimens, giving much 
precision to our knowledge of osteological characters. None of the 
families, however, are named from the typical genera; and in the 
first division (Stylodontide) we observe one genus (Dictyopyge), 
which, if Dinkel’s original drawings are correct, contradicts one 
point in the ordinal definition (“‘ Trager der unpaaren Flossen ebenso 
zahlreich als die gegliederten Strahlen”’). 
The extreme forms of the Stylodontide are <Acentrophorus and 
Tetragonolepis, and the family also includes Semionotus, Hetero- 
lepidotus, and Dapedius. The typical genus of the Sphzrodontidee 
is Lepidotus, with which are identified Plestodus, Dactylolepis, and 
Scrobodus ; and several interesting figures are given. The Muschel- 
kalk Colobodus is also placed here; and likewise the Rheetic 
Sargodon. The so-called Saurodontide (non Saurodontide, Cope) 
comprise Zugnathus, Platysiagum, Ptycholepis, Pholidopleurus, Pholi- 
dophorus, Ophiopsis, Histionotus, Macrosemius, and other genera ; and 
there is a newly determined form, Isopholis, separated from Pholi- 
dophorus on account of the less vertical elongation of the flank scales 
and the fact that the ventral scales are scarcely, if at all, broader 
than deep. There are new figures of the skull and opercular 
apparatus of Pholidophorus, Isopholis, and Macrosemius; and many 
Species are rearranged. So far as definitions are concerned, this 
family is not very satisfactorily distinguished from the Stylodontide ; 
and we suspect that one genus placed in the latter (Heterolepidotus) 
will ultimately prove identical with one of the present. family 
(Hugnathus). 
The Rhynchodontide are a well-marked family comprising Aspi- 
dorhynchus and Belonostomus; and interesting details are given, 
partly new. The Liassic B. acutus is deferred for consideration 
under Belonorhynchus; and to the comprehensive list of species we 
would only add B. laciniatus, lately recognized from the Chalk of 
