31 
The siphuncle, too, is dorsal rather than central. Corals — Michel- 
inia, Favosiies, Heliophylliim. Brachiopods — Spirifera, Orthis, 
Atiypa. Trilobites — Phacoi>s, Dalmania, Homalonotus, Fishes — 
Glyptolepis, Diplopterus. 
Cases 4A, 4B, 4C, 4D, and 5 A. — Fossils of the Car- 
boniferous Age, or age of coal plants. Naturally land plants are 
the striking features of this age. They belong to five great fami- 
lies: Conifers, Ferns, Lepidodendrids, Sigillarids, and Calamites. 
Cases 4A, 4B, 4C, 41)5 Hall 36. — Cordaites. This 
tree is allied to the Conifers, and had probably a straight trunk 60 
or 70 feet in height. Trigo7iocarpiim, in the same case, is sup- 
posed to represent its fruit. Ferns are represented by 
Neuropteids and others, many imprints of sections of the fronds 
being shown. These frequently form the center of clay concre- 
tions, as shown in some which have been broken open. Sections of 
trunks oi Lepidodendrids 2.^6. Sigillarids. One of the latter shows 
by its size that the trunk of the original tree must have been many 
feet in diameter, and perhaps 80 to 100 feet high. Stigmaria, 
which were probably the under-water stems of the Sigillarids. 
The animal life of this p'eriod is characterized by the 
abundance of Crinoids, as they reached their highest development 
at this time. Many specimens are shown in this case, including 
Platycrinus, Scaphycrinus, and Pe7itremiteSy a Blastid or bud 
Crinoid. Corals were also abundant, as represented by the 
columnar Lithostrotion, a true polyp coral, and Dibunophyllu77i, 
some polished slabs containing which are shown. The cork-screw 
like Bryozoan Archmiedes is illustrated by several specimens 
Sprifera and Prodiictus are the leading genera among the Brachi- 
opods. The Gasteropods, univalve mollusks, are represented by 
Bellerophon and PleitrotoTnaria. MeloniteSy in the upper part of 
Case4, was an Echinojd allied to the sea urchin of the present day; 
they differ from the latter, however, in having large plates and 
small spines. The cast on the wall shows the foot-prints of one of 
the first reptiles, Sauropus, This was a four-footed, crawling animal, 
with thick, fleshy feet about 4 inches long. 
Case 6A, Hall 59 . — Permian, or closing age of the Car- 
boniferous. Fishes are represented by the PalcEoniscus. Reptiles 
hy Archegosaurus,2Xi animal which combined the characters of 
reptile and fish, having both lungs and gills, and being covered 
