THE ANIMAL LIFE OF THE GROUP. 447 



may readily be placed in their pro])ei' .ueiiera by those who do not luive access 

 to more minute description. To make the ilhisti-ations more useful to those 

 whose collections are made mainly from the l)eacli. the majority of the speci- 

 mens shown are in the Ix'ach-worn condition in which they arc liahh:" to occni-. 

 They were selected from material collected on foui- holiday excursions, oiu' to 

 Waikiki and Diamond Head, one to the dredger-dumped material fiom Hono- 

 lulu harbor, one to Pearl Harbor and one to Kahana Bay. Ninety-two species 

 belonging to forty-one genera were collected in this way. Of this number six- 

 teen species belonging to fifteen genera are included in a list of foi-ty-five 

 species reported by ^Ir. D. Thaanum as commonly found on shore and in the 

 shallow water about Hilo. ]Mr. Tluianum's collection, which includes tlie land 

 and fresh-water shell collection made by the Kiduis brothers, is one of the 

 largest and most systematic private collections in the islands. The marine 

 collection numbers upwards of two hundred and fifty species belonging to 

 ninety of the one hundred and twenty or more genera commonly included in 

 a list of Hawaiian gasteropods. 



As an example of the unusual reward to be had for more exhaustive col- 

 lecting in a given locality for a single group of shells, it is interesting to report 

 that Mr. J. ]\I. Ostergaard has been able, in a few years, to secure from the 

 dredging from Honolulu harbor and other sources, thirty of the forty species 

 and sub-species of the beautiful Cijprcea, or cowry family, so far listed in the 

 literature of the subject as occurring in the Hawaiian Islands. 



The univalve or gasteropod mollusks are by far the largest division of 

 the Mollusca. Some are free swimming animals, living far from land out in 

 the open seas, but the greater number inhabit shallow water, usually about the 

 low-tide mark; while others dwell in brackish water, in fresh water and on 

 the land. The typical gasteropod — and it is only this division that can be 

 considered in any detail here — is lun'mally a crawling animal beai-ing a coiled 

 shell. They all move slowly by the continual contraction and expansion of 

 the muscular foot. Many of the common marine forms have interesting habits, 

 and may be kept alive with very little trouble in a simple salt-water aquarium. 

 In a small aquarium one should be careful not to overstock. Two of three 

 healthy, happy specimens are less trouble and far more interesting for the 

 purposes of observation and study. 



In general it will be found that the si)ecies that have the base of the aper- 

 ture rounded as in Littoriiia, Crcpidiila, Xcrifa and the like, are herbivorous in 

 habit, feeding on seaweed, moss and minute acpiatic plants. Shells in which 

 the aperture is deeply notched or prolonged into a caiuil, as in Xassa, 

 Stromhus, Mitra and Cypraa. are usually carnivorous or tlesh-eatinu' species 

 and are perhaps more difficult to supply with their accustomed food on that 

 account. 



