AMPHIPODA AM) ISOPODA OF THE FIRTH OF CLYDE. 07 



Nemevtes ncsceoides (Leach), White, Cat. Crust. 

 Brit, Mus. (1847), p. 90. 



Habitat. — All round our coasts, in the submerged 

 timbers of piers and jetties, in which this little 

 crustacean makes great havoc. It is frequently 

 associated with Limnoria lignorum, equally destruc- 

 tive to submerged timbers. 



Chelura is more than double the length of Lim- 

 noria* but not much thicker; and accordingly it gets 

 readily into the burrows of the latter. It is more 

 restless, is endowed with greater powers of swimming 

 and walking, and can leap a considerable distance when 

 out of the water ; and sometimes, when irritated while 

 out of the water, it rolls itself up like Spluvrium. 

 When put into a vessel with water, it swims for 

 some little distance, but with considerable exertion, 

 and it soon tires, and settles down on the bottom. 

 Professor Allman says : " Timber that has been 

 subjected to the ravages of Chelura yjresents a 

 somewhat different appearance from that which 

 has been attacked by Limnoria lignorum. In the 

 latter we find narrow cylindrical burrows running 

 deep into the interior, while the excavations of 

 Chelura are considerably larger, and more oblique 

 in their direction, so that the surface of the timber 

 thus undermined by these destructive animals is 

 rapidly washed away by the action of the sea, and 

 the excavations are exposed in the greater part of 

 their extent, the wood appearing ploughed up, so 

 to speak, rather than burrowed into." Where the 

 work of the two species can be seen on separate 

 pieces of timber (which I have not had the oppor- 

 tunity of observing), I have no doubt the difference 

 in the direction and size of their burrows will be 

 quite noticeable. Yet, on splitting up a piece of 

 timber off the piles of Millport pier, both Chelura 

 and Limnoria were found in the yjerforations, these 

 being to all apx^earance of the same depth, and 

 excavated in the same direction ; and although 

 Chelura, as stated, is much larger than Lrimnoria, 



