27 
belongs to the class of sponges. Aspidosoma , Furcaster — Aster- 
oids. Spirifer , Orthis — Brachiopods. Goniatites — represent the 
Cephalopods. They are of the same type as Orthoceras , but are 
coiled and the junction of the septa and shell (suture) is zigzag in- 
stead of straight. Bothriolepis — Ganoid fish. Note the thick, bony 
plates or armor. 
Cases 4A, 4B, 4C, 4D, and 5A. — 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 
families: Conifers, Ferns, Lepidodendrids, Sigillarids, and Cala- 
mites. 
Cases 3A, 4B, 4C, 4D, Hall 36. — Cordaites . This tree is 
allied to the Conifers, and had, probably, a straight trunk 60 or 70 
feet in height. Trigonocarpum , in the same case, is supposed to 
represent its fruit. Ferns are represented by Pecopteris , Neurop- 
teris and others, many imprints of sections of the fronds being 
shown. These frequently form the center of clay concretions, as 
may be seen in some which have been broken open. Sections of 
trunks of Lepidode?idrids and 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 , prob- 
ably represent the under-water stems of the Sigillarids. 
The animal life of this period is characterized by the abun- 
dance of Crinoids. These reached their highest development at 
this time. Many specimens are shown in this case, including 
Platycrinus y Scaphycrinus and PentremiteSy the latter a Blastid or 
bud crinoid. Corals were also abundant, as represented by the 
columnar Lithostrotion , a true polyp coral, and Dibunophylluniy 
a cup coral. The cork-screw-like Bryozoan Archimedes is illus- 
trated by several specimens. Spirifer and Productus are the 
leading genera among the Brachiopods. The Gasteropods, uni- 
valve mollusks, are represented by Bellerophon and Pleuro tom- 
aria. Melonites y in the upper part of Case 4, was an Echinoid 
allied to the sea-urchin of the present day; it differs from the lat- 
ter, however, in having large plates and small spines. A cast on 
the wall shows the foot-prints of one of the first reptiles, Sauropus. 
It was a four-footed, crawling animal, with thick, fleshy feet about 
four inches long. 
Case 5A, Hall 59. — Permian, or closing age of the Car- 
