34 Prof. M'Intosh's Notes from the 



by the reproductive elements. The main point in Mr. Wood- 

 uorth's observations was the demonstration of the atokous 

 and epitokous regions of the body in situ, and as obtained 

 by splitting the edges of the honeycombed coral-rocks. 

 The author attaches much importance to what he calls the 

 thcrmotropic or heliotropic reaction of the pigment-specks 

 borne on the best-developed central segments of the 

 epitokous region — in connexion with swarming. Further 

 observations are necessary on this head, since similar features 

 are observed in other forms without such pigment-specks. 



In the Atlantic " Palolo ■" {Eunice fucata, Ehlers) from 

 the Dry Tortugas and Porto Rico, a careful account of Avhich 

 was given in 1892 by A. G. Mayer *, a very similar condition 

 prevails, the posterior epitokous or sexual region being 

 thrown off by the annelids wiiich live in canals and crevices 

 of the dead and disintegrating coral-rock or corroded " co- 

 quina/^ sometimes along with the commensalistic Polynoe 

 granulata, Ehlers. These sexual posterior regions are broader 

 than in the Pacific '' Palolo,'^ and present no pigment-spots, 

 but swim freely away in the same manner — constituting the 

 swarming, which occurs within three days of the moou^'s last 

 quarter, June 29th to July 28th. 



In Britain a condition closely approaching that seen in 

 the foregoing " Palolo " occurs in various forms, e. g. in 

 Nereis Burner i/ii, Aud. & Ed., swarms of which are seen in 

 various bays. Thus they were in vast numbers in Castlcbay, 

 Barra, in May, aud were captured by Dr. Thomas Scott, of 

 the staff of the Fishery Board for Scotland. '' Millions " of 

 Nereis longissima were also found by Mr. Hoarder swimming 

 at the surface in Plymouth Sound in 1865. Like other 

 Nereids this is likewise a favourite bait. An allied condition, 

 that is free-swimming sexual forms, occurs in the Syllideaus, 

 the Cirratulids [Dodecuceria) , and many other annelids. 



Amongst others Verrill f mentions Nectonereis inegalops 

 as a form which " swims actively at the surface both in the 

 evening and in the brightest sunshine in the middle of 

 the day, from July 3rd to August 11th. In this species 

 the palpi appear to be much diminished in the Heteronereis 

 condition (unless it has some connexion with Ceralonereis). 

 The males and females of Nereis irritahilis, Wel)ster, when 

 mature, also take to swimming on the surface in the beginning 

 of August. The immature examples live near low-water 

 mark in sand and mud on the Virginian coast. 



* Brooklyn Inst, of Arts & Sc, Sc. Bullet, vol. i. no. 3, pp. 93-103, 

 ] plate, Dec. 1902. 

 t •' Invert. An. Vin. Sound," U.S. Comm. F. & F. 1873, p. 592. 



