BREEDING HABITS OF LIMNORIA AT BEAUFORT, N. C. 



By R. E. CoKER 



Notwithstanding: the general interest that is periodically mani- 

 fested 4n destructive marine borers of all kinds, there has been a 

 notable lack of definite information regarding the essential features 

 of life history of most species. This applies particularly to the little 

 isopod, Limnoria lignonim, which is of extremely wide distribution 

 and particularly destructive in Southern American waters. Lim- 

 noria has been observed and collected in innumerable localities — on 

 the Atlantic coast from Florida to the Gulf of St. Lawrence, in the 

 Pacific Ocean, in the North Sea, in the Adriatic, on the coast of 

 Great Britain, etc.^ Yet there are practically no references in the 

 literature to examples carrying eggs or embryos in the brood pouches. 



Through the courtesy of the United States Bureau of Fisheries 

 and the interested and efficient cooperation of ]Mr. Charles Ilatsel, 

 Superintendent of the U. S. Fisheries Biological Station, Beaufort, 

 N. C, periodic collections of Limnoria from wharf piles on Fivers 

 Island, Beaufort, N. C, have been made for me for a period of more 

 than a year, beginning May 1, 1922. Only a preliminary examination 

 of the material has yet been made; but, in view of the fact that a 

 number of agencies and investigators are now engaged upon experi- 

 ments to determine means of prevention of the attacks of marine 

 borers of all kinds, including Limnoria, it is worth while to give out 

 the information available regarding the breeding season and habits 

 of Limnoria. 



As is true of other isopods, development in Limnoria is direct, the 

 eggs being carried in infra-thoracic pouches until the young isopods 

 are fully formed and set free to begin boring into the wood probably 

 in close proximity to the maternal parent.^ The eggs or embryos found 

 in a pouch are almost invariably of approximately identical condition 

 of development, indicating that the entire brood is deposited in the 

 pouch at one time. A single exception to this rule was noted with an 



1 Richardson, Harriet. Monograpli of the Isopods of North America. Bulletin U. S. 

 National Museum, No. 54, Washington, 1905. Richardson recognizes but one species in- 

 cluding all examples in the National Museum, from whatever part of the world. 



-Observations on new borings at Woods Hole, Mass., indicate that a sexual pair is 

 commonly found in a single burrow, the female being nearest the blind end of the burrow. 

 This suggests that the female does the work of excavation. 



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