POLYt'HiETA OF THE L.M.]^,.C. DISTRICT. 183 



together in the old genus Pohjiu)?, togetlier with Johnston's 

 Poll] nor scolopendrlna which however might peril aps with 

 advantage be removed to a separate genus. 



CoMMEXSALisM. This favourite habit of the Polynoina^ 

 is well illustrated in the following pages. To summarize 

 the local facts on this point we have Nijchia cirrosa and 

 Polyno? setosisslma living in the tube of Chcutopterus 

 uisig)iis; Poly nor castcoiea upon the test of Spatangus 

 purpureus ; P. lunulata and AcJioIor astericola in the 

 ambulacral groove of Astropecten irregularis ; P. joJuiston i 

 in the tube of Thelepus cincinnatus ; Herniadion assimile 

 close to the mouth of Echinus esculent us, and finally the 

 nearly allied species H. peUucicluni has been found upon 

 three different kinds of star-fishes. 



Lepiclonotus squconatus, (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 Pohjno'r 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. 



Njjchia cirrosa, (Pallas). 

 Hab : B, 5, 7. Low w'ater of spring tides to 18 fms. ; 

 sometimes commensal wdth Chcetopterus insignis and 

 Thelepus cinci)inatus. 



Malmgren [loc. cit.) w^as the first authority to recognise 

 this to be an undoubted British species. He found that 

 certain British Museum specimens named Lepiclonotus 

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

 Beaumaris, X. AA'ales, in the majority of cases belonged 



