319 



miilation of yolk are found in the middle part of the ovary. In this region the nucleus 

 shows long, fine radiations in contrast to the round nucleus of the early egg. The longi- 

 tudinal section figured shows -two small eggs and the larger eggs in the middle part 

 of the ovary. The pair of oviducts is shown in the cross section iovd.. fig. 130, 2). 

 They open on the ventral side of the fifth free thoracic segment. 



The reproductive organs in the male were not studied closely. According to 

 Hoek (1893), they consist of the testes, the vasa deferentia and the penis. The testes 

 are in the last thoracic segment and in the same relative position as the ovaries of 

 the female. They continue into the vasa deferentia, which open on the ventral side 

 of the last thoracic segment, in the median plane of the body. The penis is implanted 

 in a posteriorly directed fold of the skin. Hoek suggests that this fold takes the place 

 of the copulatory scale which is found in Idothea. 



During the growth of the ovarian eggs, some \er\- striking changes occur. The 

 eggs grow to a large size and the accumulation of yolk in the egg is so great as to 

 occu]iy about two-thirds of the interior of the organism. The other organs are pushed 



Fig. 132. Linnwria lignonim, photographed ali%e in position in burrows. X 12. 



to one side. The digestive tract is tightly compressed and the livers pushed closely 

 against it. It was noticed that no wood could be found in the digestive tract at this 

 time. 



The Boring H.\hit of Limnori.\. 



The boring habit will be considered together with the methods of distribution of 

 Limnoria and the initiation of attack. The possibility of distribution over long dis- 

 tances, from harbor to harbor, has been considered above in connection with the 

 cosmopolitan nature of the organisms. It should be mentioned that the practice of 

 taking in ballast water is quite common with harbor freight boats and may also be a 

 factor in the local distribution of this pest. 



