Some of our crustaceans are only partially protected by a firm outer covering, and almost every attempt to preserve these as dry objects results in such a shrivelling of the soft tissues that the natural appearance is quite destroyed. This is the case with some of the barnacles, and the abdominal portion of the bodies of hermit crabs, which are, therefore, far better preserved in fluid. Dilute spirit is quite satisfactory for most of these as far as the preservation of the soft structures is concerned, but it has the disadvantage that it turns the shells of some crustaceans red, making them appear as if they had been boiled. Other crustaceans are so small, or are hardened externally to such a slight extent, that they also are not adapted for the dry method of preservation. Speaking generally, such crustaceans as shrimps and sand-hoppers are best preserved in fluid, while the different species of crabs and lobsters are more conveniently preserved dry unless it is desired to study any of their soft structures. It is quite impossible to remove the soft parts from small crabs and lobsters previous to drying them, hence the drying should be conducted as rapidly as possible, so that no decomposition may set in. Where the process goes on very slowly, as is the case when the air is damp, or when the specimens are not set out in an airy spot, a decay of the soft structures soon proceeds, and the products of this decay will generally saturate the whole specimen, giving rise to most objectionable odours, and destroying the natural colour of the shell. If it has been found that the species in question are not reddened by the action of methylated spirit, they should be allowed to remain in this fluid, with a few grains of dissolved corrosive sublimate, for at least a few hours, and then they will dry rapidly without any signs of putrefaction; and even those species that _are_ reddened by spirit may be treated to a shorter immersion in this fluid with advantage. The specimens should always be set out in some natural attitude to dry, unless it is desired to spread out the various appendages in some manner that is more convenient for the study of their structure. A sheet of blotting-paper may be placed on cork or soft wood, the specimens placed on this, and the appendages kept in the desired positions when necessary by means of pins placed beside, but not thrust through them. When more than one specimen of the same species has been collected, one should be set in such a manner as to exhibit the under side; and, further, in instances where the male and female of the same crustacean differ in structure, as is commonly the case, two of each should be preserved, one displaying the upper, and the other the under surface. When perfectly dry, all small crustaceans should be mounted on cards with the aid of a little gum, and the name and other particulars to be remembered then written on the card.