of a few Annelids. 249 



of these young worms are not lost (as in other Annelids, where 

 the ringed bristles are always temporary), but remain to form 

 in the adult a brush of long bristles on the posterior side of the 

 dorsal cirri (see fig. 43). With the lower bunch of smooth setse 

 we find the row of hook-shaped bristles first noticed in fig. 41 ; 

 in fig. 42 we have already from five to six of these bristles at 

 the anterior rings. The upper brush of serrated bristles is 

 found in specimens measuring no less than 4 inches in length, 

 not raised in confinement, but collected on the beach, where 

 they are found in company with Pohjdora, but by no means so 

 common. Along the middle of each ring, on the dorsal side 

 of the younger stages (figs. 39, 40), we find a row of short 

 vibratile cilia ; similar rows, less numerous, of larger cilia occur 

 on the lower side. The anal ring terminates, in the adult, in a 

 simple opening with slightly corrugated edges (fig. 45). 



The general mode of development is so similar to that of 

 Leucodora given by Claparede, and of Polydora as figured in 

 the present papel*, that only those stages have been introduced 

 which tended to elucidate the comparison with figures pre- 

 viously published resembling them. The resemblance between 

 the young larvae certainly warrants the affinity between Ne~ 

 rine, Spio, and Pohjdora, suggested by Claparede (who places 

 them with the Aricia3), and does not justify us in associating the 

 former with other families, as has been done by Quatrefages in 

 his Systematic Table, and thus bringing them in close relation- 

 ship with groups having a totally different embryonic develop- 

 ment, such as Phyllodoce and Nereis. The species of Nerine here 

 investigated is probably the Nerine coniocejjhala of Johnston"^. 



Phyllodoce maculata, Oersted f. 

 Max Miiller is thus far the only one who has observed laiTse 

 of PhyllodoceX', from his description they must have been in 

 a condition nearly identical with the oldest larvse here repre- 

 sented (fig. 52). The youngest stages (figs. 46, 47) have a 

 slight resemblance to the larvje of Polyno'e figured by Sars§, 

 Max Miiller II, and Claparede^. We find in these earlier stages 

 a very powerful ring of vibratile cilia extending round the 

 middle of the anterior part of the animal, but no trace of cilia 



* Mag. Zool. and Bot. 1838, ii. pi. 2. figs. 9-13, p. /O. 



t Grbnlands Annulata dorsibranchiata, 1843, pi. 3. fig. 46, p. 39. 



X Note on p. 17, iu Arcliiv f. xVnat. u. Phys. 1855. 



§ *' Zur Entwickelung der Anneliden," in Archiv f. Nat. 1845, i. p. 11, 

 pi. 1. fig. 12. 



II " Leber die Entwickelung u. Metamorpliose der Polynocn," in Archiv 

 f. Anat. u. Phys. 1851, p. 223, pi. 13. 



H Beobaclitungcn, pi. 8. figs. T, 8. 



