642 REVIEWS. 
of exploration of Dr. Hayden, or that of the Kansas Pacific Rail- 
` road, and that of Professor B. F. Mudge of the State Agricultural 
Co lege. 
During the period when the Cretaceous ocean extended from 
Eastern Kansas over the present site of the ai bps 
and from the Gulf of Mexico to the Arctic Sea, it abounded 
in life. Among vertebrata, fishes and marine nib chiefly 
abounded, and in varied forms. ‘Many of the reptiles were char- 
acterized by a size and strength exceeding that seen in any other 
period of the world’s history. The species of Sauropterygia and 
Pythonomorpha were all aquatic, but the two types present very 
different adapt ations to their mode of life. While the former pos- 
sessed two pairs of limbs the latter “appear to have possessed an an- 
terior pair only, or with the posterior pair so reduced as to have 
been insignificant. They substituted for them an immensely long 
and flattened tail, which they used, like the eels and sea-snakes, 
as an oar. The Sauropterygia were ae tag stout-bodied and 
with a very markedly distinct neck. In t e Pythonomorpha, on 
the other hand, the body was snake-like, vith narrow chest and 
neck scarcely differing in diameter. They were immensely elon- 
gate, and might be called sea-serpents with Freri propriety. 
f Sauropterygia, Polycotylus had a slender neck and very 
stout limbs ; but in Elasmosaurus the neck attained dimensions ex- 
ceeding that of any vertebrated animal. The species E. platyurus 
was probably the longest of the order, measuring perhaps fifty 
feet, but of this the neck amounted to twenty-two feet. The crea- 
ure was carnivorous, and could no doubt like the snake-bird, swim 
at a considerable distance’ below the surface of the water and reach 
to the surface for air, or explore the depths or plunge for fishes to 
the depth of forty feet. 
Among the Pythonomorpha the Liodon dyspelor is the largest 
species and the Clidastes intermedius the smallest. A specimen of 
Mosasaurus Missuriensis obtained by William Webb near Topeka 
is stated by him to measure seventy-five feet in length. Should 
this be substantiated the L. Kang was at least one-third larger. 
This is, ini as yet uncertai 
The upper arm bones of the Clidastes are remarkably short er 
wide and furnished with strong processes for the insertion of mu 
cles. They are e among reptiles much like those of moles ee 
quadrupeds, and, as in the latter, indicate probably great power of 
propulsion in the fore limbs. The finger bones were long an d 
slender and formed a a tong fin or flipper, while the upper arm was 
probably concealed in the skin. The whole limb came off but 4 
short distance posterior to the head. These re 80 far as 
known were all carnivorous ; their food was chiefly fishes 
His notes on the fossil fishes are of much interest :— 
“The laminated rock from which the above species were ob- 2 
i 
i 
a 
me 
4 
= 
a 
al 
; 
