312 NEREIS DIVERSICOLOR. 



is carried on without metamorphosis. (2) A small pelagic Heteronereid which is found 

 at Naples in February and March. (3) A tnbicolous Heteronereid form of large size which 

 occurs in June and July. He gives a careful and well-illustrated account of the segmenta- 

 tion of the egg and the general development of this species up to the formation of the 

 embryo. The species is stated also to be viviparous. A hermaphrodite form Avas found 

 at La Hougue by Caullery and Mesnil ] amidst Lithoth amnion. 



De St. Joseph 2 (1895) mentions that the homogomph bristles do not appear in the 

 dorsal division except in the anterior part of the body ; thus in a ripe female Nereid of 

 eighty segments they appeared at the forty-first segment ; at the thirtieth segment in a 

 small example of 30 mm. and sixty segments. The last had a vibratile fossa on each 

 side of the head between the posterior eyes and the base of the tentacles. He also notes 

 that the intestine of an example contained Doliocystis nereidis, a gregarine. 



The same author 3 more recently describes a new species (0 era toner eis punctata) from 

 St. Raphael, the foot of which approaches that of N. Dumerilii somewhat closely. 



6. Nereis diveksicolor, 0. F. Midler, 1771. Plate LII, figs. 4 and 4a; Plate LX, figs. 11 

 and 11a — head; Plate LXXII, figs. 5-5 J — feet; Plate LXXXI, figs. 5-5 & — 

 bristles. 



Specific Character*. — Head somewhat triangular and mottled with brownish pigment. 

 Tentacles about a third the longitudinal diameter of the head. Palpi in life end in tapering 

 extremities. Eyes of moderate size situated far back. Tentacular cirri of moderate 

 length, the dorsal of the second pair being longest, and considerably exceeding the 

 diameter of the body. Body 3 — 4 ins. in length, and of 120 bristled segments. Peristomial 

 segment about twice the breadth of the succeeding. Tail terminating in two caudal cirri. 

 General colour yellowish-brown, dusky anteriorly and greenish at the sides — from the feet, 

 which are also vascular. Proboscis with two brownish maxillae translucent at the base ; 

 teeth five to seven. Paragnathi are small. Dorsally, in extrusion, the maxillary division has 

 a band (II) of small teeth on each side and one or two (I) in the middle line. Ventrally at 

 the base of each jaw is a slightly curved belt of minute teeth (IV), narrower in front, 

 broader behind, and directed nearly longitudinally. Between them is a broad belt (III) 

 of small teeth, formed in some of a series of longitudinal rows of about three teeth, but in 

 others they are less regular. The proximal segment has dorsally a group (VI) of small 

 paragnathi (five to eight in number) on the eminence in front of each palpus. Ventrally 

 a basal belt (VII and VIII) of minute teeth stretches from side to side, but with a gap 

 between it and the dorsal groups. The first foot is distinguished by the three long, pointed 

 conical lobes, the indistinct setigerous process, and the short cirri. The dorsal lobe 

 increases to the tenth foot, and is also of considerable size at the thirty-seventh. Both 

 setigerous lobes become prominent. The ventral lobe soon diminishes. Foot generally 

 presents an uneven outline when viewed from above, the second and third lobes being 



1 c Ann. d. Univ. de Lyon/ Bd. x, fasc. xxxix, 1898. 



2 ' Ann. Sc. Nat./ 7 e ser., t. xx, p. 214. 



s Ibid., 9 e ser., t. iii, p. 219, pi. iv, figs. 90—93, pi. v, figs. 94, 95. 



