96 
POPULAR SCIENCE REVIEW. 
methods. At the same meeting Mr. Seeley read a paper on the Potton 
Sands. — Applying these principles to the Potton Sands of Bedfordshire, he 
considered that the lower deposits were of the same age as the Portland sands 
of the South of England ; the middle fossiliferous seams of the age of the 
Purbeck heds ; and the upper deposits of the Lower Greensand. 
On some Points in the Structure of Xiphosura . — At a late meeting of the 
Geological Society, Mr. W. Woodward, the accomplished editor of the 
Geological Magazine, read a valuable paper on the above important palaeon- 
tological subject. He pointed out that Professor McCoy’s tribe, Pcecilopoda, 
was intended to include the Limuli, with Eurypterus, Pterygotus , and Beli- 
nurus. Professor Huxley had already shown (in 1859) that this classification 
was founded upon an erroneous interpretation of the fossils, then (1849) 
only known in England by extremely fragmentary remains. Professor 
MHoy’s classification was based on conjecture rather than on a minute 
acquaintance with the anatomy of these extinct forms. The subsequent 
researches of Professors Agassiz and Hall in America, Professor Nieszkowski 
in Eussia, and the independent investigations of Mr. J. W. Salter and the 
author in this country, have shown that a close relationship actually does 
exist between the Xiphosura and the Eurypterida. Mr. Woodward then 
gave a detailed comparison of the structure of these two divisions, which 
he proposed to call suborders of Dr. Dana’s order Merostomata. He pointed 
out that the Xiphosura were divisible into three genera: (1) Belinurus 
[BailyJ, having five freely articulated thoracic segments, and three anchylosed 
abdominal ones and a telson; (2) Prestwichia, a new genus, having the 
thoracic and abdominal segments anchylosed together ; and (3) Limulus 
[Muller], having a head composed of seven cephalic and one thoracic seg- 
ments, followed 1 y five coalesced thoracic somites bearing branchiae, and 
one or more coalesced apodal abdominal somites, to which is articulated the 
telson. Although so great a dissimilarity exists between Pterygotus and 
Limulus, yet in the genera Ilemiaspis, Exapinurus, and Pseudoniscus , we 
have forms which, in the number of body-rings, are intermediate. 
On the Dinosaurian Reptiles of South Africa. — Professor J. H. Huxley, in 
a paper he read before the Geological Society, describes a portion of a right 
femur 25* inches long, so that the entire femur may be safely assumed to 
have exceeded 30 inches in length. The peculiar form of the bone and the 
character and position of the trochanters leave no doubt of the Dinosaurian 
affinities of the reptile to which it belonged, which must have been com- 
parable, in point of size, to its near allies, the Megalosaurus and the Igua- 
nodon. To the former of these it possesses the closest affinity, but differs in 
the proportional size and form of its trochanters, and in its much heavier 
proportions ; and the author proposes for , it the name Euskelosaurus 
Brownii. Professor Huxley also described a portion of the distal end of a 
femur, indicating another genus of large-sized Dinosaurian reptiles, the 
characters yielded being to prove that it belongs to another genus than 
Euskelosaurus . 
Secondary Fossiliferous Deposits of New South Wales. — These have been 
very carefully examined by the Bev. W. B. Clarke, who has recently given 
a description of them to the Geological Society. It appears that until the 
year 1860 secondary deposits were thought to be absent from Australia. 
