200 ARICIAD^, 



glass. The antennae can be directed to any point, and are capable 

 of being rolled up in a spiral form (fig. 11). There is a good deal 

 of complexity in the structure of the feet, which renders their de- 

 scription and delineation difficult : they are lateral, and deeply divided 

 uito a dorsal and ventral branch, which is compressed, and armed 

 with a series of retractile bristles of unequal lengths, and to each 

 bi'anch there is affixed a rounded plain compressed lobe, probably a 

 modification of the cirrus of other Annelides, The bristles are sim- 

 ple, curved, and acutely pointed, those of the dorsal branch longer 

 than those of the ventral, and there is a small fascicle of longer ones 

 at the root of the branchial filament (fig. 3). The feet are appa- 

 rently alike along each side until within a few segments of the tail, 

 when the branchial filaments become very short or disappear, and 

 the ventral branch seems to acquire a superior development, and to 

 be armed also with longer bristles (fig. 4). The anus is dorsal in 

 its aspect, and is surrounded with eight short equal papillae, which 

 assume a star-like form when the aperture is dilated. 



The Nerines inhabit the sea-shore and the margins of rivers, a 

 little below high-water mark. They prefer a soil composed of sand 

 and mud, and in which the latter rather preponderates. They are 

 found lurking under stones, or burrowing in the soil ; and in the 

 latter situations the surface to a great extent is seen full of small 

 round perforations, and covered with little heaps of its tubvilar and 

 spiral excrements. When disturbed, they descend in their furrows 

 with great rapidity, and to a considerable depth ; when taken, they 

 throw themselves into violent contortions, as they " were waxed 

 mad," during which the body generally separates into several por- 

 tions, or loses its antennse, which always separate at their very base. 

 Their several portions retain their vitality for at least some days, 

 which they evince not merely by their contortions when pricked, but 

 even by moving from one place to another. The animals are named 

 "Rag-worms" by the Berwickshire fishermen, and are used in their 

 neighbourhood as bait to take the fry of the coal-fish. 



This genus is evidently very different from any characterized by 

 Audouin and Milne- Edwards. I have seen two species, of which 

 the characters are : — 



I . N. vulgaris, head obtuse and lunated in front ; antennse origina- 

 ting from the sides ; anal papillae eight. Length 4" ; breadth 2'". 

 Plate XVII. figs. 1-8. 



Spio vulgaris, Johnston in Zool. Journ. iii. 335 & 4S7- 



Neriue vulgaris, Johnston in Mag. Zool. Sf Bot. ii. 70. pi. 2. f. 1-8. 



Williams in Ann. ^ Mag. Nat. Hist. ser. 2. xii. 408. pi. 14. f. 8. 



Grube, Fam. Annel. 66. 

 Nereis aries — Ram's-liorn Nereis, Dalyell, Pow. Great, ii. 148. pi. 20. 



f. 3-6. 



Hub. The shore between tide-marks, ascending tidal rivers as far as 

 the water is made brackish. 



Desc. This worm is from 3 to 4 inches in length, of a yellow- 



