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tions of another animal, the Limnoria terebrans, of Leach, belong- 

 ing to the class of Crustacea, whose depredations on timber are no 

 less extensive and formidable than the Teredo. At Portpatrick it ap- 

 pears that both these animals have combined their forces in the work 

 of destruction, the Teredo consuming the interior, and the Limnoria 

 the superficial parts of the wood ; the latter continuing its labours 

 until it comes in contact with the shells of the former, so that the 

 whole mass is speedily deprived of cohesion. It is stated, on the au- 

 thorities of Mr. Hyndman and Mr. Stephen, that the Limnoria is al- 

 ready committing great ravages in the timber at Donaghadee. 



2. " On the Nervous System of the Sphinx ligustri (Linn.) during 

 the latter Stages of its Pupa and its Imago States; and on the Means 

 by which its Development is effected." By George Newport, Esq. 

 Communicated by P. M. Roget, M.D., Sec. R.S. 



In a paper formerly read to the Royal Society, and printed in the 

 Philosophical Transactions, the author has given a description of the 

 anatomy of the nervous system of the Sphinx ligvstri in its larva, and 

 the earlier periods of its pupa, state ; and he has since prosecuted the 

 inquiry then commenced, following the changes of structure through 

 the remaining stages, until the insect has arrived at its full develop- 

 ment. He enters into minute details of all these changes, which 

 vary considerably in the rapidity with which they take place at dif- 

 ferent periods, according as the vital powers are called into action by 

 external circumstances, or become exhausted by their efforts at effect- 

 ing the growth or modifying the form of different parts. Thus the 

 ganglia and nervous cords undergo great changes both in their form 

 and situation, and also in their number, during the passage of the 

 insect from the larva to the pupa state j and after these changes have 

 been carried to a certain extent, they are suspended for several weeks, 

 during which the insect remains in a state of hybernation ; but at the 

 expiration of this period the changes again proceed, and are continued 

 uninterruptedly, til! the insect attains its ultimate or perfect stage of 

 development. The Sphinx ligustri remains in the pupa state during 

 at least forty-two or forty-three weeks ; thus affording ample oppor- 

 tunities of examining the whole progress of the changes which take 

 place in the structure of different parts. The concentration of the 

 nervous system, which was commenced in the larva, proceeds to a 

 mucn greater extent while the insect is inclosed in the pupa, and is 

 continued for a short time after it has assumed the imago state. The 

 double origin and connexions of the nerves distributed to the wings 

 are described, and a conjecture offered as to the object of this ar- 

 rangement, which appears designed to establish a harmony of action 

 between the wings, in those insects, especially, which are remarkable 

 for velocity and power of flight; a different disposition being adopted 

 in those which fly with less regularity or speed. The nerves of the 

 organs of sense, as the antenna?, eyes, proboscis, and apparatus for 

 manducation, are traced and minutely described, and a comparison 

 instituted between them and the nerves which have similar offices in 

 vertebrated animals. The author traces the origin and course of the 



