THE MUSEUM. 



II 



.dividuals are found witli ripe sexual 

 products durinj,' the early part of Au- 

 gust, and the \oung derived from eg^s. 

 laid at this time must continue to set 

 till September or later. In the second 

 place, the younjj were setting in the 

 wood abundantly till the middle of 

 August, a fact which indicates that the 

 same continues to some degree for 

 some time longer. Of course, from 

 an economic standpoint the period 

 durinj:; which the wood is attacked is 

 one of the most vital points to dis- 

 cover. 



"The number of young produced is 

 ama/ing, estitnated in one case at 

 from a single very large female one 

 hundred million, and while the greater 

 part are lost before the setting stage 

 is reached, yet the number that set is 

 very great, and one of the most dis- 

 couraging features in dealing with 

 shipworms in a practical way. If the 

 spat were of fairly appreciable size 

 and set in but moderate numbers, it 

 might be feasible, by the careful re- 

 moval of all old piles and other old 

 timbers, to sufficiently reduce the 

 number to a minimum. But when, 

 .under favorable conditions, over a 

 hundred to the square inch set where 

 there is not room for more than one 

 .or two to reach maturity, it is 

 easily seen what an excess is always 

 present, and how futile it is to try to 

 .combat the larvae before they enter 

 the wood. 



"The practical way, of course, is to 

 prevent their entrance into the wood 

 •by protecting the wood with copper 

 , paint and sheeting. With small piles 

 and timbers it would seem to be worth 

 while to try various means of keeping 

 the bark on the wood, which, so far as 

 the writer knows, has not been done; 

 for it is well known that as long as the 

 bark is on timbers they are not at- 

 tacked by shipworms. 



"Once the shipworm has set into 

 the wood it grows with amazing ra- 

 pidity in our Southern waters. In 

 twelve days it has grown to be an 

 eighth of an inch long: in twenty days 



about half an inch; and in thirty-six 

 days four inches, when it is thousands 

 of times as large in volume as when it 

 sets. It has become sexually mature 

 and is ready t > produce a new genera- 

 tion. How I .ug shipworms may live 

 has never been observed, though it is 

 probably several years, and that dur- 

 ing this time they keep growing, if 

 there be room in the wood for growth; 

 though when crowded the individuals 

 become dwarfed. The writer has 

 found specimens of great size of T. 

 Norvegica, some three to four feet 

 long, and it is easily seen how de- 

 structive may be a few of these in- 

 dividual which may become almost an 

 inch in diamater. The age of such 

 specimens I have not been able to de- 

 termine, but it is estimated to be less 

 than two years. 



"In the colder waters of Long 

 Island the writer has found specimens 

 of both T. navalis (.') and Xylotrya 

 fimbriata, the former more abundant. 

 They seem to set more abundantly 

 after the ist of July, though observa- 

 tions for one season cannot be con- 

 clusive. The rate of growth is much 

 slower and it would seem to take twice 

 as long to attain the same size as in 

 the warmer Southern waters. 



"The writer in his studies of the 

 shipworms has paid most attention to 

 features purely scientific in their in- 

 terest. 



"Observations, to be of any dif- 

 ferent economic value, must cover a 

 variety of localities under different 

 conditions, and must extend through a 

 period of years — observations which 

 the writer has not had sufficient op- 

 portunity to make and which for our 

 American forms have unfortunately 

 never been made." 



Florida Land and Fresh Water 



Shells. Also Centipedes, Scorpions, Crabs, 

 etc. in alcohol at a bargain. Address with 

 stamp. 



O. BRYANT, 



LoDgwood, Florida 



