NEPEIDJE. 259 



Hacker (1896) describes and figures the metatrochophore stage of Nereis with three 

 pairs of feet and three pairs of eye-specks, and later 1 (1898) a Nectochaste stage with four 

 bristled segments and two eyes. In Nereis limhata the prototroch appears in ten hours, 

 in another twenty hours it swims as a monotroch, and in two and a half days it assumes 

 what he calls a three-segmented Nauplius-stage. It ceases to be pelagic about the 

 twelfth stage. This author groups the Nereids with the Nephthydicla?, Phyllodocidse, 

 Eunicidse, and Aphroditidaa in having a secondary nectochsete stage. 



The Nereids are generally found in tubes between tide-marks or near low-water 

 mark — sometimes under the nest of Amphithoe, at others in an independent dwelling in 

 fissures of rocks, under tangle-roots, in decayed stalks of the same sea-weed, or in 

 sponges. They also frequent the laminarian and coralline regions, and range to consider- 

 able depths, as in certain examples from the ' Challenger,' and those frequenting holes in 

 telegraph cables. Some occur in masses of peat, either having made the tubes or having 

 driven out those which made them, and others occupy tubes composed of fragments of 

 shells, corallines, algse, sand, gravel, and secretion ; or the tubes are more or less 

 transparent. Many are found in the stomachs of cod, haddock, and other fishes at St. 

 Andrews. Mr. Cyril Crossland communicates a note on a brilliant orange-red Nereid, 

 common at Dongonab in the Red Sea, in a thin collapsible tube attached throughout its 

 length. If the annelid is removed and placed in a vessel of sea-water, the tube is rapidly 

 re-formed. They are muscular annelids that wriggle most dexterously out of the forceps, 

 but unlike the common eel do not always make good use of their opportunities on the 

 ground, though they swim with vigour and agility. They soon die when kept with 

 other collections in a bottle, and rapidly putrefy. Their skins are extremely sensitive to 

 vapour of alcohol. 



A few Nereids are commensalistic, like Nereile/pas fucata with the hermit crab in the 

 shell of Buccinum, and the orange species procured by Prof. Giarcl 2 in the folds of 

 Balanoglossus 3 on the rich sandy beaches of l'lles Glenans. The unarmed proboscis and 

 the reduced condition of the dorsal lobe of the foot with its simple bristles would indicate 

 its relationship with Lycastis, species of which have been found at Rochelle and elsewhere 

 on the shores of France. 



Some devour other annelids, Crustacea, and sponges, the spicules of which occur in 

 their intestines; whilst others, like Nereis Dumerilii and N. cultrifera,Sire partial to Algaa. 



All the British forms are marine, though N. pelagica moves far up the inlets in 

 North Uist, and N. diversicolor also is found in brackish regions; Cuvier, indeed, 

 suspected that true Nereides may be found in the lakes of North America, though the 

 reasons for this view are not stated. A considerable number of foreign species, however, 

 occur in fresh water and many in brackish water. 4 Such forms chiefly pertain to the genus 



1 ' Plankton Exped. Polyclnet./ p. 9, Taf. 1, figs. 3 and 3 a. 



' 2 Since this was written the distinguished French naturalist Las died. He was one of the 

 foremost marine zoologists of his day in Prance, and equally esteemed in other countries. 



3 ' Compt. Rend./ Aug. 21, 1882, p. 389; < Ann. Nat. Hist./ 5th ser., vol. x, p. 230. 



4 Interesting accounts are given by C. Gravier, ' Bullet. Soc. Philomathique de Paris/ 1901, and 

 1905, pp. 1—12, sep. copy. See also H. P. Johnson, ' Mark. Anniv. Vol./ art. x, pp. 208—223, pis. 

 xvi and xvii, 1903. 



