620 EXHIBIT AT THE COTTON STATES EXPOSITION. 



Nos. 8 to 136 represent the class Gasteropoda. Of these, Nos. 06, 67, 

 70 to 75, and 129 to 132, are families which inhabit fresh water; Nos. 

 119 to 128 are terrestrial, and the remainder for the most part live in 

 the sea. The shell of the Gasteropods is typically spiral, but varies 

 from a mere flat plate like that concealed under the mantle of Limax, 

 through conical, tubular, and coiled forms to the regular spiral. Nearly 

 all spiral shells are dextral (right-handed), but some few families or 

 genera are sinistral (left-handed), as for example the Achatinellidce 

 (No. 118). The Gasteropods include a large number of useful orna- 

 mental species. Among those of economic importance are the Buc- 

 cinida'j the Littorinidcv, and the Trochidce, many of which are used for 

 food. 



No. 137 represents the class Scaphopoda. The shells of some of this 

 class are used by the Indians for making wampum. 



Nos. 138 to 199a represent the class Pelecypoda or bivalves. Most 

 of these are marine, but Nos. 179 and 180 live in fresh water. Many 

 are beautiful and valuable, while others are injurious. The wood borers 

 (No. 141) destroy the piling and the planking of vessels and dry docks. 

 Some of the Mytilidce and Ostreidw are edible. The Aviculidce produce 

 pearls and mother-of-pearl. 



The class Brachiopoda, which doubtfully belongs with the Mollusca, 

 was extremely abundant in past geological ages, but is now represented 

 by only a few species, most of which inhabit deep seas. 



DEPARTMENT OF INSECTS. 



This display occupied the wall space in Alcove F, and was of course 

 very far from completeness either as an exhibit of insects or as an illus- 

 tration of the wealth of material in the entomological collections of the 

 Museum. Here, thanks to the pains of Prof. C. V. Riley, the limited 

 space had been utilized to admirable advantage. The exhibit is 

 described by him as follows : 



The chief exhibit, arranged in twenty-four frames, is designed to 

 illustrate the peculiarities of the various families of insects. It is 

 limited to Hexapods, or insects proper, and does not include the Spiders, 

 Mites, and Myriapods, and in fact some of the families of the true insects 

 are necessarily omitted. The object of this family exhibit is a two- 

 fold one: First, to give the student the salient characteristics by which 

 he may be able to refer any insect to the family to which it belongs, and 

 also to illustrate what are considered as family characteristics as com- 

 pared with the larger and lesser groupings or alliances. The second 

 object is to give a very good exhibit of the North American fauna, 

 since by selecting types illustrative of each family the beholder gets a 

 very fair impression of the character of the North Ainerican insect 

 fauna, the family illustrations all being drawn from North America. 



The second portion of the exhibit is designed to relieve the monotony 

 of a series prepared solely for instruction by adding something pleas- 

 ing to the eye. Thus eight frames have been arranged as a sort of 

 attractive entrance to the alcove. These consist of beautiful Lepidop- 

 tera and Coleoptera which have been purposely chosen from the four 



