Geology and Mineralogy. 269 
tially as in the older work. In the Brachiopoda the only 
important change is in adopting the grouping of the Articulata 
suggested by Waagen, though with some change in the names, viz: 
Aphaneropegmata, Helicopegmata, Ancistropegmata (=Campylo- 
pegmata p. p. Waagen) and Ancylopegmata (=Ancylobranchia 
Gray, Campylopegmata p. p. Waagen). 
The Mollusca are distributed in the five classes, Lamellibranch- 
tata, Scaphopoda, Amphineura (adopted from Ihering), Gastro- 
poda and Cephalopoda. Neumayr’s natural separation of the 
Anisomyaria from the Homomyaria is recognized in the cbassiti- 
cation of the Lamellibranchiata; also his classification of the 
latter order into the sub-orders Toxodonta, Pachyodonta, Hetero- 
donta and Desmodonta. . 
Fischer’s division of the Nautiloidea and Ammonoidea respec- 
tively into Retrosiphonata and Siphonata is discarded. Bathmo- 
ceras is placed in the family Orthoceratide, and JWVothoceras in 
the family Nautilide. The position of the siphon is made of 
, prime importance in the Ammonoids, viz: A. the Jntrasiphonata, 
with the single family Clymeniide, being separated from B. the 
EHatrasiphonata, which includes the other families of the sub- 
order. iS 
The three sub-orders Belemnoidea, Sepiodea and' Octopoda are 
recognized in the Dibranchia. 
_ The important modification of the breathing apparatus in the 
Arthropoda is made of sub-branch rank, thus separating the 
Branchiata, with the single class Crustacea, from the Tracheata, 
with the three classes Myriapoda, Arachnoidea and Insecta; the 
old divisions, Entomostraca, Malacostraca and Merostomata 
being retained as of sub-class rank. 
As a result of the great differentiation discovered by Brongniart 
in the Carboniferous Insects of Commentry, Scudder’s grouping 
of the Paleozoic Insects into Paleodictyoptera is discarded, and 
all the fossil Insects are distributed in the recognized existing 
orders, the Aptera being raised to ordinal rank. 
Very few changes are made in the classification of the Verte: 
brates, the two volumes of the “Handbuch ” on this branch havy- 
ing been move recently written. We, however, note the elevation 
of the Leptocardii, and the Cyclostomi to class rank, of which no 
fossil remains are reported, and the Placodermi to the rank of a 
sub-class, separating it from the Ganoids and placing it between 
the Selachii and the Dipnoi. Among the Mammals, the Adlo-. 
theria of Marsh is reduced from ordinal to sub-ordinal rank, and 
the families of the Marsupialia are distributed in the three sub- 
orders Allotheria, Diprotodontia and Polyprotodontia. In the 
class Placentalia, Ameghino’s Litopterna and Cope’s Ancylo- 
poda, the genera of which were previously considered in the sub- 
order Perissodactylia, are given the rank of distinct sub-orders in 
the order Ungulata. 
The book is fully illustrated; each of the important groups is 
opened with a general description of structure and parts, and 
Am. Jour. Sc1.—Tsikp Series, Vou. L, No. 297.—SEPTEMBER, 1895. 
18 
