( 3) 



ter,"* and exceedingly thick and strong. 



The operations of the teredo sug- 

 gested to that distinguished civil engin- 

 eer, Mr. Brunei, his method of tunneling 

 the Thames River, f 



Having glanced at the xyloiDhagous 

 mollusks, we will now turn briefly to the 

 wood -eating Crustacea, to which the 

 species referred to by Dr. Hewston be- 

 longs. 



The order of Isopod (or equal-footed) 

 crustaceans inhabit the land and also 

 fresh water and marine stations. As an 

 illustration of their general form we 

 may refer to the terrestrial wood-lice 

 { Onisc idee) v.'hich inhabit gardens, cel- 



WOOD-LOUSE. 



SwrjiMiNG Rock-louse. 



lars, and other damp places, and which 

 are called by the children, "sow-bugs." 

 The Isopoda are divided into three 

 sub-orders: First, the Ambulatonj, or 

 walkers; second, the Ncdatonj, or swim- 

 mers; third, the Sedentary, or inactive 

 Isopods. 



Many of the species are parasites in 

 their habits, and some live in the gills 

 or on the tails of fishes; some live in the 

 I bronchial cavity of the land-crab; others 

 in the same portion of the sea -crabs, 

 shrimps, and prawns. 



The Limnoria terebrans, which is the 

 species so destructive to marine wood- 

 work in Great Britain, belongs to the 

 1 sea wood-lice, and is the only species 

 • in that genus. Whether the form exhib- 

 ited by Dr. Hewston belongs to this 

 genus or to the genus Chelura among 



* t Woodward's Manual of Mollusca, 2ud 

 ed., p. 507. 



the Aniplupoda, another order of Crusta- 

 cea, and which includes a species known 

 as Chelura terebrans, remains to be de- 

 termined. The last-named species was 

 discovered some years ago at Trieste, 

 boring into wood-work in sea-water. 



A species of Chelura is also found in 

 Australia, and it is not improbable that 

 the species recently found in this harbor 

 may belong to one of the species I have 

 named, and have been imported on the 

 bottom of vessels from some of the 

 ports with which we hold commercial 

 relations. 



With the shijj-worms and sea-lice op- 

 erating as in the specimen submitted by 

 Mr. Arnold, a most careful inspection 

 of all submerged wood-work connected 

 with harbor imjirovements on the coast, 

 is absolutely necessary, or great loss of 

 property and perhaps bodily injury may 

 eilsue. So far as protecting piles by 

 saturation with some chemical, obnox- 

 ious to the animals referred to in this 

 paper, and which will measurably retain 

 said quality for a reasonable length of 

 time, and resist neutralization by the 



LlMNOEIA TEBEBHANS. WhITF. (SoLDIEK) AnT. 



sea -water, experiments carefully and 

 considerately made are certainly war- 

 ranted, and any process by which a 

 successful result should be obtained, 

 would justify a very considerable ex- 

 pense, and still be good financial econ- 

 omy. 



Before closing, I will mention another 

 family of wood- eaters, the Termites, or 

 white ants, which in some parts of the 

 world are exceedingly destructive; they 

 are principally confined to tropical 

 countries. " When they attack wood- 



