2o0 PRELIMINARY OBSERVATIONS ON A NATURAL HISTORY 



a small prawn trawl, and some interesting phosphorescent Ostracoda 

 by the use of the towing net. These I propose to make the subject 

 ol a future communication. Of the worm tribe, class Annelida, a 

 small collection was made including representatives of the two 

 leading groups distinguished by the respective titles of the 

 Dubicola and Errantia. Among the last-named section one equally 

 interesting type, Bonellia, was taken in some abundance with the 

 dredge in Cambridge Gulf. 



The brief opportunity of landing on the Cairncross and Howick 

 Islands in the Great Barrier system was utilised to collect several 

 specific forms of the commercial varieties of the Beche-de-mer, 

 Trepangs, or Sea Cucumbers, as they are popularly called, and which 

 belong to that section of the Echinodermata, including also the 

 Sea-urchins and Starfishes, known technically as the Holothuroidea. 

 The examples collected, so far as I have been able to identify them, 

 would appear to represent the four species figured and described in 

 Semper's work on this particuliar group, under the respective titles 

 of Holothuria atm, H. aculeata, H. scabra, and H. vjtellus. It 

 afforded me much interest in studying the habits of these animals 

 in their native coral reefs to find that their method of feeding, 

 which has frequently been a subject of discussion, is essentially 

 identical with that recorded by me of certain of the smaller English 

 Bpe sies, some years since, in the pages of "Nature." The operation 

 is accomplished with the assistance of their proliferously capitat e 

 oral tentacles, and with which — while crawling over the submerged 

 rocks, or quietly resting in the tide-left pools — they gather up every 

 detachable organic substance and convey it to their mouth. First, 

 one tentacle is swept mop-wise over the rock or ground within 

 reach, and is then reflexed and thrust bodily into the oral cavity. 

 Immediately one tentacle is withdrawn, another food-laden tentacle 

 is reflected and ready to take its place, and in the same manner al^ 

 of the, from ten to twenty, tentacles are kept actively work in 

 supplying the commissariat. The substances found within the 

 alimentary cavities of these Holothurine on dissection, consist chiefly 

 of fragments of coral, molluscous shells, and sand. Also to a very 



