230 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



together in the old genus Polynoe, together with Johnston's 

 Polynoe scolopendrina which however might perhaps with 

 advantage be removed to a separate genus. 



Commensalism. This favourite habit of the Polynoinse 

 is well illustrated in the following pages. To summarize 

 the local facts on this point we have Nijchia cirrosa and 

 Polynoe setosissima living in the tube of Chcetopterus 

 insignis ; Polynoe castanea upon the test of Spatangus 

 purpureus ; P. lunulata and Acholo'e aster icola in the 

 ambulacral groove of Astropecten irregularis ; P. johnstoni 

 in the tube of Thelepus cincinnatus ; Hermadion assimile 

 close to the mouth of Echinus esculentus, and finally the 

 nearly allied species H. pellucidum has been found upon 

 three different kinds of star-fishes. 



Lepidonotus squamatus, (Linn.). 

 Stations:— 6, 7, 8, 10, 12, 13, 14; H, P, M. (From 

 between tide marks to 22 fms). 



This widely distributed form is more frequently found 

 in deep water than Polynoe propinqua. The most prolific 

 ground was in 18 — 20 fathoms, Porthwen Bay, Anglesey, 

 where a large number were dredged. These were of a 

 greater size than any elsewhere procured, and the largest 

 were very strongly marked on the elytra. Many of the 

 warts towards the postero-internal direction were filled 

 with very conspicuous black pigment. 



Nychia cirrosa, (Pallas). 

 Hab : B, 5, 7. Low water of spring tides to 18 fms. ; 

 sometimes commensal with Clmtopterus insignis and 

 Tlielepus cincinnatus. 



Malmgren (loc. cit.) was the first authority to recognise 

 this to be an undoubted British species. He found that 

 certain British Museum specimens named Lepidonotus 

 cirratus v. parasiticus, W. Baird, and hailing from 

 Beaumaris, N. Wales, in the majority of cases belonged 



