G76 ON A NEW CRUSTACEAN, 



ON A NEW CRUSTACEAN FOUND INHABITING THE 



TUBES OF VERMILIA (SERPULID^.) 



By William A. Haswell, M.A., B.Sc. 



[Plates XXXVI. and XXXVII.] 



While examining a stone obtained from about low-water mark 

 at Watson's Bay for living iSerjndce, I found inhabiting the 

 tube of a Vermilia in several instances an Isopodous Crustacean 

 which is in many respects very remarkable. In some points 

 the animal shows relationships to known families of Isopoda 

 — notably the Anthuridae ; but it has become to some extent 

 specially modified in accordance with its peculiar mode of life. 

 The body is narrow and vermiform, the telson and terminal 

 appendages very wide, the other appendages very small ; the sides 

 of the body are ornamented with long seta?. The whole appearance 

 of the animal is singularly like that of a small Serpula, the oper- 

 culum and branchiee being mimicked by the expanded posterior 

 appendages and telson, and the hairs representing the pai'apodial 

 seta?, while the smallness of the limbs and the vermiform shape of 

 the body, aid in perfecting the resemblance. That the presence of 

 these Crustaceans in the Serpida-tuhes was not a mere accidental 

 occurrence was shewn by the fact that the three which I first found, 

 all of which were females, had each a brood of embryos with them 

 in the tube, and not in any way connected with them. After 

 finding those three in Serpula-tuhes all quite near one another on 

 the same stone, I found another on the surface of the stone. This 

 I found to differ in several respects from the others, not possessing 

 the long hairs, and being white instead of red ; it is probable it 

 had escaped from one of the tubes that was broken open. On 

 another occasion I found in the same spot three more individuals 

 of the same species, two of which svere females like those I had 

 previously found, while the third differed from them very 

 remarkably in shape, being extremely elongated and filiform. 

 Each of these, including the last, which I conclude to be a male, 



