HISTORICAL COLLECTIONS. 
83 
Among numerous other groups which cannot be mentioned 
great interest attaches to the Trilobites (fig. 57) of the Palseozoic 
epoch. These creatures are related to the King- Crabs of the 
Moluccas, and both have affinity with the Scorpions. 
Very extensive is the collection of Fossil Plants from the 
Coal-Measures, among which Lejpidodendron and Sigillaria, 
as well as numerous kinds of fern-like leaves, are among the 
most common. 
The fifth gallery is set apart for the reception of certain 
Fig. 51.— Upper {A) and Lower {B) Surfaces of Pteriohthys, 
AN ARMOURED DEVONIAN FiSH. 
special collections of historical interest, either from the circum- Historical 
stances under which they were formed or came into possession 
of the Museum, or from their containing a large number of type 
specimens described and figured in various publications. Hence 
it has been considered undesirable to break up and disperse 
these among the general collection. They include the original 
collection formed by William Smith, the pioneer of geology in 
this country, the Searles Wood Collection of Crag Mollusca, 
the Edwards Collection of Eocene Mollusca, the Davidson 
