210 Remarks on the Affinities 



by enabling the ships to lie alongside at all times without 

 impeding their repairs. It appears from Mr. Stevenson's 

 experiments, that the Limnoria attacks every kind of wood 

 which he employed, except teak ; where this cannot be ob- 

 tained, the wood may be coppered or coated with iron nails, 

 in which case it is necessary to extend the coating, at least 

 six inches under the surface of the ground, as it has been 

 sometimes found that the protected piles have been attacked 

 by the animals obtaining access below the last row of nails. 

 Common tar and sulphur mixed have been found ineffectual 

 by Mr. Stephen at Donaghadee, but'paint seemed to succeed ; 

 gas-tar and pitch are effectual for a time, but all of these are 

 liable sooner or later to be washed off, in exposed situa- 

 tions, by the violence of the sea. Impregnation with some 

 poisonous materials, as Kyan's patent solution, promises to 

 be of service, as it is understood to protect the wood for a 

 certain distance from the surface, which is the point at which 

 the Limnoria begins its operations ; I have recently submitted 

 Kyanized wood to this test, and in a few months I shall 

 probably be able to state the results of the experiment; in the 

 mean time the best defence seems to be the employment of 

 teak entirely, or sheathing the piers with it, or in default of 

 that, I should recommend the more exposed timbers to be 

 coated with iron nails, and the others to be carefully painted. 



Plymouth, January, 1838. 



Art. VI. Remarks on the Affinities of Lythracew and Vochyacece. — 

 By Sir E. F. Bromhead, Bart. F.R.S. L. and E. 



The formation of botanical alliances has placed the question 

 of affinity on a new footing, and affords tests unknown before. 

 It is not now sufficient to derive relations from a comparison 

 of the extreme deviations in two families ; their normal struc- 

 ture must be compared ; and above all, the joint- affinity must 

 be estimated from the normal structure of the particular alli- 

 ance in which the family must be placed under the supposed 

 affinity. 



Lythracea offer a fair example of the principle. The older 

 botanists compared them with the labiate plants, on ac- 

 count of their mere aspect ; but the character of the Lamia- 

 les, (as to the limits of which I quite agree with Dr. Lindley), 

 will at once settle the question : — 



LAMIALES. Stems round or tetragonal, with perfect nodes, not lac- 

 tescent ; stipules 0. Inflorescence not gyrate. Calyx persistent, odd caly- 



