NERINE. 199 



and spreading, often clothed with large vibratile cilia. Miners in 

 wet sand or mud, or dwellers in slightly cemented sand-formed tubes. 



* With two long tentacula-like antennae. 



23. NERINE*. 



Nerine, Johnston in Mag. Zool. ^ Bot. ii. 68 (1838). Williams in 

 Rep. Brit. Assoc. 1851, 199, 213, 234, and f. 18. Grube, Fam. 

 Annel. 6Q. 



Char. Body vermiform, subquadrangular : head small, distinct : 

 mouth subinferior, with a very short edentulous proboscis : eyes mi- 

 nute : antennae two, occipital, large, long and tapered : branchiae 

 forming an uninterrupted series of short tapered ciliated filaments 

 along each side, reflected on the back, with a lobe at their base : feet 

 all alike, well developed, biramous, each branch consisting of a com- 

 pressed lobe and a short pedicle armed with simple bristles : anus 

 stellated with a circle of papillae. 



Obs. The body of the Nerines is elongated and vermiform, nar- 

 rowed a little at the head, and tapered gradually towards the anal 

 extremity ; it is somewhat quadrangular, and is formed of numerous 

 narrow segments. Each segment has on each side, affixed to its 

 dorsal margin, a subulate branchial process, as long as the semidia- 

 meter of the animal, and of a fine red colour, which proceeds from 

 two large blood-vessels running up within it. A cuticular fold or 

 membrane invests the base of each branchial filament, and mounts 

 along the side to an extent which varies with its position ; for on 

 the filaments of the anterior third of the body the membrane rises to 

 the very apex and is comparatively broad, but posterior to this the 

 point of the filament is free, and still further back the membrane 

 gradually shortens until it at length is no longer to be traced, — the 

 branchiae at the same time becoming gradually less, and ultimately 

 obsolete on the caudal segments (PI. XVII. figs. 12, 5, 6, 13). When 

 in water the branchiae are raised and extended, and in almost con- 

 stant movement ; but when the worm is removed from the water, 

 they are laid across the back, their points meeting in the middle, 

 giving the body the appearance of being marked with transverse folds 

 or elevated striae. They are fringed on both margins with a single 

 series of vibratile cilia, discoverable with a magnifier of common 

 powers ; but these cilia are deficient on the apex, as well as on the 

 lobe, while they extend over the dorsal arch of the segments (fig. 3). 

 The head is furnished with two large slightly tapering antennae 

 which originate from the occiput, and which are often cast off in the 

 struggles of the animal : they consist of two large central vessels 

 filled with red blood, and coated with a white mucous skin, which, 

 when magnified, appears roughish or crenulate ; and one side has a 

 row of minute cilia, not, however, to be seen except with a good 



* Nerine, a patronymic of tlie daughters of Nereus. 



