SCIENTIFIC SUMMARY. 
211 
tarsal bones were not co-ossified with the long bones, and the third trochanter 
of the femur was rudimentary or wanting. 
Professor Marsh describes a still larger species of Atlantosaurus (A. irn - 
manis) which had a femur over eight feet long, which, taking a crocodile as a 
term of comparison, gives the fossil animal a length of about 115 feet ; and 
the author thinks it probable that the reptile when alive was nearly 100 feet 
long, though it may have been much less. Another species, called Morosau- 
rus impar, allied to Apatosaurus and Atlantosaurus , is best represented by its 
sacrum, which is said to indicate an animal at least 25 feet long. The genus 
Allosaui'us (see p. 104) is said to present characters which render it the type 
of a distinct family of Dinosaurs, Allosauridce , and a new species (A. lucaris) 
18 or 20 feet long is described. 
Creosaurus atrox, allied to Lcelaps , an animal about 20 feet in length, is 
said to have been “the carnivorous enemy of the huge Atlantosauridce .” 
The teeth referred to it have more or less trihedral crowns, with the cutting 
edge crenulated. The vertebrae are biconcave. 
As a contrast to the preceding giants we have Laosaurus celer, a Dinosaur 
about the size of a fox, and L. grasilis, a still smaller species. — Silliman’s 
Journal , March, 1878. 
Carboniferous Sponges. — Numerous remains of spicular bodies, believed to 
belong to sponges, have been recently detected in the Carboniferous shales 
of the south-west of Scotland, and described in more or less detail by Pro- 
fessor J. Young, Mr. J. Young, and Mr. H. J. Carter, in several papers pub- 
lished in the “ Annals and Magazine of Natural History ” (see especially 
ser. 4, Vol. XX., p. 425, and ser. 5, Vol. I., p. 128). The most interesting 
part of the evidence points to the existence in Carboniferous times of a 
sponge so nearly allied to the well-known glass-rope, that the above authors 
do not hesitate to refer it to the same genus, and it is here described under 
the name of Hyalonema Smithii. With regard to other species the evidence 
of affinity with recent forms is less striking. Mr. Carter has some important 
remarks on the replacement of silica bv carbonate of lime in these fossils. 
MECHANICS. 
An Automatic Railway Brake . — In “Nature,” March 21, 1878, we find a 
description of an automatic brake made by the Westinghouse Brake Com- 
pany, and an account of some experiments on the action of a current of 
compressed air upon an elastic ball, which possess considerable interest. 
The article is really a report of experiments witnessed at the Company’s 
offices, where the writer was shown the action of the whole apparatus 
necessary to stop a train of ten carriages. The apparatus works by means 
of air, which is compressed by a steam engine, and distributed through all 
the tubes and the ten reservoirs, extending over the whole length of the 
train ; by simply turning a handle this compressed air acts upon the brakes, 
which, in turn, clasp the wheels; the action is so completely under control 
that the brakes can be applied in less than 5 seconds, and so powerful as to 
bring a train going 40 miles an hour to a dead stop in about 15 seconds, and 
within a distance of 500 yards. 
The mode of action is as follows : — The compressed air is admitted into a 
p 2 
