NEPHTHYS. 169 



lines across the base of the feet. Feet greatly developed, increasing 

 gradually in size to about the middle of the body, whence they 

 again decrease towards the tail, very deeply divided into two branches : 

 the dorsal branch rather less than the ventral, furnished with a per- 

 pendicular lamellar somewhat ovate process, with a small appendage 

 of the same character at its base, a small cirrus, and an elongate 

 branchial filament curved like a reaping-hook ; the setigerous pro- 

 cesses obtuse, broad, shorter than the lamellse ; the inner armed 

 with a row of long, and the outer with a row of short bristles : 

 ventral branch much like the dorsal, the lamella larger, with a 

 small cirrus at its base. Bristles dusky, longer than the processes, 

 very slender, setaceous, smooth, simple, each brush with a brown 

 spine. The short bristles look as if they were abruptly broken oif, 

 but they are uniform on all the feet, and appear to be pointed 

 under the microscope. Anus terminal, superior ; the segment small, 

 apodous, terminated with a style. 



This worm is remarkable for the splendour of its colour, which 

 is exactly similar to that of mother-of-pearl ; but the silvery lustre 

 is confined to a space down the back and belly, for the sides and 

 feet are of a yellowish hue, the inner base of the feet reddish, and 

 the bristles dusky. When the foot is removed, and placed under a 

 magnifier, it has a sort of resemblance to a horse's hoof; and is 

 a very wonderful and beautiful piece of mechanism. The creature 

 lives in the sand, in which it burrows by means, principally, of its 

 strong proboscis. With this, used as a wimble, it opens up the way, 

 the body being held steady with the aid of the setigerous feet. It 

 thus buries itself with almost incredible velocity : nor is it less active 

 in the water, should it accidentally be removed from its furrow and 

 cast in the open sea, — swimming rapidly, with a serpentine wriggling 

 motion, and propelled, unquestionably, by the lamellae which project 

 from each side, like a double bank of oars. 



From Nephthys Homhenjii our species diflFers very much in the 

 constructioxi and form of the processes of the feet ; while in the 

 shape and colour of the body they seem very nearly to agree. To 

 no other species which has been accurately defined can it be referred ; 

 but ours may be conjectured to be the Nereis clavn of Leach. I 

 have no means of deciding the point ; and Blainville has, it would 

 appear, introduced such an almost inextricable confusion into the 

 nomenclature of that species, that it might be scarcely advisable to 

 restore the name. The figure he has given {Diet. pi. fig. 1) does 

 not facilitate the solution of the question. 



To the marine Annelides in general, fresh water is a deadly poison 

 {Loud. Mag. Nat. Hist. ii. p. 402*) ; and Dr. Drummond has told 

 its eifects on the Nephthys in an interesting manner : — " On putting 

 one of them," he says, "into a basin containing some fresh water it 

 sank to the bottom, and lay for a moment motionless, as if stunned. 

 It then dashed here and there through the water, violently lashing 

 its anterior and posterior ends from side to side ; but this extreme 



* " II est meme a remarquer qu'il est peu d'etres marins qui meurent aussi 

 \ite quand ou les met dans de Teau douce ; il semble que ce soit pour eux une 

 liqueur corrosive." — Blainv. Diet, des Sc. naf. Ivii. p. 409. 



