148 NEREID.^:. 



of the same length. Head narrow. Eyes very distinct. Antennse 

 not projecting beyond the palpi. Proboscis roughened as usual with 

 black horny spinules. Jaws of a light horn-colour, pellucid, with 

 eight triangular stout teeth not reaching to the point, which is plain. 



No. XXIII. — Nereis brevimana. 



Tentacular cirri unequal, the longest setaceous, in length fully twice 

 that of the diameter of the segment. Rings about 88, narrowed 

 posteriorly, the anal one terminated with rather long styles. The 

 inferior branchial lobe becomes smaller as we trace the feet back- 

 wards, and near the middle of the body forms almost a part of the 

 setigerous tubercle (fig. m), the union being still more complete on 

 the posterior pairs of feet, on which also there is a mere vestige of 

 the ventral cirrus (fig. p). The colour of some of the specimens in 

 spirits becomes a wax-yellow, with a tinge of brown, and a dusky 

 line across the margin of the segments. 



This species very closely resembles Nereis pulsatoria, but in the 

 latter the jaws are serrated to the apex, and the terminal joint of the 

 bristles is finely serrulated along one edge. The specific character 

 of Rathke is very applicable. 



Obs. About 3 inches long, and larger than an earthworm of the 

 same length. The colour is discharged from specimens preserved 

 in spirits, and I have not seen a living specimen. 



{a) Plymouth. 



(5) Ayrshire, P. W. Maclagan, M.B. 



2. N. pelagica, post-occipital segment about twice as long as the 

 second ; tentacular cirri longer than its transverse diameter j jaws 

 with ten obtuse denticulations ; lobes of the feet papillary, obtuse, 

 subequal, the dorsal more or less humped ; superior cirrus twice as 

 long as its lobe ; terminal piece of the bristles smooth. Length 8". 



Nereis pelagica, Linn. Syst. x. 654 ; xii. 1086 ; Faun. Suec. 2nd edit. 

 608. Bast. Opusc. Subs. ii. 133. tab. 6. f. 6, cop. in Encyclop. M^th. 

 Vers, pi. 55. f. 21-23. Johnston in Ann. Nat. Hist. v. 172. f. 3, 4. 

 Oersted, Ann. Dan. Consp. 21. tab. 4. f. 7'2, 75 & 76; Groenl. An- 

 nul. Dorsibr. 23. f. 52, 53. 



Hab. The littoral region ; and ascends tidal rivers as far as the 

 water continues brackish. 



