NEREIS (PERINEREIS) MARIONIL 299 



cone with glands dorsally and ventrally and a great blood-vessel in the centre. The short 

 dorsal cirrus is now at the tip of the region, in a line with the dorsal border, a small 

 rounded papilla beneath indicating the dorsal lobe. The dorsal setigerous lobe is 

 represented by its bristles and the spine. The lobe beneath is considerably less. The 

 inferior setigerous lobe and the parts beneath have the same character as in the previous 

 foot. 



Behind the sixty-eighth the characters of the foot present little alteration, even to the 

 tip of the tail. The greatly elongated and very slightly tapered dorsal region has the short 

 cirrus at its extremity, and the deeper angle at its base inferiorly is now the only trace of 

 the dorsal lobe. The upper setigerous lobe is represented by its spine and a few bristles. 

 The lobe beneath is ovate, but its base encroaches on that of the region above it. The 

 inferior setigerous lobe is conical, the longer slope being ventral. The ventral lobe is 

 small, but of similar shape to that in the sixty-eighth foot. The ventral cirrus projects as 

 far as the tip of the setigerous lobe above it. The vascularity of the entire foot is great, 

 so that the posterior region of the animal is thus provided with a series of leaf -like organs 

 for aiding, along with the other parts of the foot, in respiration. The bristles preserve 

 the same characters as in the sixty-eighth foot ; two of these in the inferior series with 

 short tips arise above the spine, and are stronger than the others. 



Habits. — This species is less active than Nereis pelagica, N. cultrifera, or N Dumerilii, 

 and is considerably smaller than the two former species. 



An example from Falmouth in the British Museum is labelled Nereis fimbriata. 

 Considerable confusion, indeed, has occurred in the synonymy of this species, the 

 characters of which, however, are, on the whole, distinctive. The variability and com- 

 parative feebleness of the paragnathi, and their tendency to become indistinct in spirit- 

 preparations, may also have tended to create doubt. These remarks are suggested by the 

 fact that Baron De St. Joseph, whose admirable work on the Annelids of Dinard and 

 generally of the shores of France has done so much to clear up the subject and increase 

 our knowledge of the group, does not include Nereis Marionii, And. & Edw., in his compre- 

 hensive series. Yet he constitutes two new species for forms having the closest resemblance 

 to that of Audouin and Edwards. The first of these is one which he places under the 

 genus Neanthes of Kinberg, viz., Nereis (Neanthes) Perrieri, 1 which he procured at 

 Villerville and Villers on the shores of France. It is true the longest tentacular cirrus is 

 longer than that usually found in N Marionii, and the paragnathi show certain differences, 

 but, as Horst 2 has already pointed out, a considerable margin should be allowed for 

 variation, and he is of opinion that this form is only the Nereis succinea of Leuckart, a 

 form here considered synonymous with Nereis Marionii, Aud. & Edw. 



The second species, viz., Perinereis longipes, he doubtfully associates with the Nereis 

 crassipes of De Quatrefages 3 and of GrubeV critique on the Annelids in the Parisian 

 Museums; but it appears to be this form (Nereis Marionii), so well known in the 

 Mediterranean, on the southern shores of England, and in the Channel Islands. De St. 



i ' Ann. Sc. Nat./ 8 e ser., t. v, p. 288, pi. xv, figs. 69—77, 1898. 



2 Vide p. 301. 



3 ' Anneles/ i, p. 550. 



4 < Arch. f. Naturges./ 1870, p. 305. 



