KEYIEWS. 
213 
then in the eleven following chapters he describes the several varieties of the 
osseous, muscular, nervous, digestive, absorbent, circulatory, respiratory, 
excretory, tegumentary, and reproductive systems of Fishes and Reptiles. 
He does not simply divide the Haematocrya into Fishes, Batrachia, and 
Reptiles ; but forms the following sub-classes : — Dermopteri, Teleostomi, 
Plagiostomi, Dipnoa, and Monopnoa, which he thus defines. The members 
of the first have the body vermiform and limbless, the endo-skeleton carti- 
laginous and devoid of ribs, the skin scaleless, no sympathetic nerve, eyes 
wanting, branchial function independent of mouth, no amnios. The type 
of this sub-class is the Ammocaetes. The second is known by a fish-like 
body, with fins supported by rays ; in most the endo-skeleton is more or less 
ossified, the skin is covered with scales, the brain has a prominent mesen- 
cephalon, there is a sympathetic nerve, the mouth admits the respiratory 
currents, the branchial openings are two — one on each side, — there is no 
amnios or external allantois. This group includes the ordinary fishes and 
the ganoids (Sturgeon, Lepidosteus, Pterichthys) properly so called. Sub- 
class three is formed to embrace the Sharks and Rays. The species included 
in it have a cartilaginous skeleton, a mouth which in most is a wide, trans- 
verse slit, opening below the head, an intestine with a spiral valve, a pancreas 
and spleen, a bulbous arteriosus, with numerous valves, gills fixed, and with 
several branchial openings ; the embryo is without allantois or amnios, and 
has deciduous external gills. The fourth sub-class, Dipnoa, corresponds to 
the ordinary Amphibia ; and the fifth, Monopnoa, is the equivalent of 
Reptilia. 
The best part of this voluminous work is that upon the dermal structures, 
which is enriched with illustrations from the author’s splendid “ Odonto- 
graphy.” In the remaining chapters, there is little that will not be found 
in the works of Bojanus Stannius and other writers. Had Professor Owen 
consulted more fully even his own original memoirs, he would not have 
produced a treatise which is diffuse without being comprehensive, is as full of 
fancies as of facts, and is as out of accordance with recent progress as it is 
unworthy of his own great name. 
POPULAR ZOOLOGY* 
M UCH as dry-as-dust naturalists may decry popular treatises, it is certain 
that works which are sufficiently devoid of technicalities to be under- 
stood by general readers are in great favour with the public. Not a week 
passes by but what produces some popular scientific treatise, and in fifty per 
* “ Sea-side Studies in Natural History.” By Elizabeth C. Agassiz and 
Alex. Agassiz. Boston : Ticknor & Fields. London : Trubner. 1865. 
“The Structure of Animal Life.” By Louis Agassiz. New York: 
Schreibner & Co. 1866. 
“ Our Reptiles.” By M. C. Cooke. London : Hardwicke. 1865. 
“British Beetles.” By E. C. Rye. London : Lovell Reeve. 1866. 
“A Plain and Easy Account of the Land and Fresh-water Mollusks 
of Great Britain.” By Ralph Tate, F.G.S. London : Hardwicke. 1866. 
