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X. On certain Points in the Anatomy of the Polynoina, and on the Polynoe' (Lepidonotus, 

 Leach) clava of Montagu. By Alfred Gibbs Bourne, B.Sc. Lond., Univ. Scholar 

 in Zoology, and Assist, in the Zoological Laboratory, University College, London. 

 (Communicated by Prof. E. Ray Lankester, M.A., F.L.S.) 



(Plates XXXIV.-XXXVI.) 



Bead January 18th, 1883. 



THE investigation of the anatomy of the Polynoe clava of Montagu was undertaken, at 

 the suggestion of Professor Lankester, by Mr. W. B. Benham, Demonstrator in Zoology, 

 University College, London. Mr. Benham made a large series of drawings, comparing 

 this species with Polynoe squamata ; but while working at the Zoological Laboratory at 

 Naples, I was enabled to examine a very large number of living specimens of Polynoe, 

 more especially of P. grubiana, Clap., which I shall show to be only a variety of our 

 P. clava ; and as I had obtained certain new results with regard to the anatomy of that 

 and other species of Polynoe, Mr. Benham kindly placed his notes and drawings in my 

 hands. 



I do not propose to deal at any length with questions of synonymy. The enormous 

 mass of literature upon the group, the number of species which are now known to exist, 

 and the minute characters which separate them, combined with the very general cha- 

 racter of most of the descriptions of the older writers, render it undesirable to do so on 

 the present occasion. Polynoe clava was first described from the coast of Devonshire, 

 by Montagu * as Aphrodita clava ; and he fully distinguished between this form and 

 P. squamata, Linn. ; his single figure, however, is insufficient. 



Johnston t also distinguishes between this form and P. squamata, and gives the fol- 

 lowing characters : — 



" L. squamatus. — Scales ovate and reniform, imbricate, granulous, ciliated on the outer margin ; 

 tentacula and tentacular cirri incrassated below the point ; bristles of the ventral branch with sharp 

 denticles on the thickened portion of the 'shaft below the smooth talon-like apex. Length 1-2"; 

 breadth 3'"." 



" L. clava. — Scales subcircular, margined, not imbricate nor meeting on the mesial line, maculated, 

 unciliated on the edge ; tentacular and dorsal cirri bulbous below the point ; bristles as in L. squamatus. 

 Length IV; breadth 4"'." 



Claparede seems to have overlooked the species entirely, and describes his P. grubiana 

 as differing from P. squamata, Linn., in its elytra not covering the back, in the smooth 

 contour to the elytra, and in the papillate character of the palps. 



Mcintosh \ points out that Claparede's P. grubiana may be a variety of Lepidonotus 



* Montagu, Linn. Trans, ix. p. 108, t. 7. fig- 3. 

 t Johnston, ' A Catalogue of British Non-parasitical Worms,' 1S65. 

 X ilclntosh, Trans. Zool. Soc. is. 1877, p. 371. 

 SECOND SERIES, ZOOLOGY.— VOL. II. 49 





