160 THE ANNELIDES. *§> 149. 



With the Dorsibranchiati, the many delicate threads which arise from 

 ihe cerebral ganglion by special roots and pass to the difi'erent portions of 

 the dio-estive canal with a ganglion here and there upon their course, may 

 be regarded as splanchnic nerves/^^ 



With the Amphinomae, Euniceae, Nereideae and Ariciae, there arise 

 from the posterior border of the cerebral ganglion two roots which may be 

 rewarded as Nervi pharyngei superiores, and which unite near their origin 

 into a Ganglion pharyngeum superius. From this last pass off posteriorly 

 delicate threads which form many ganglia upon the oesophagus, and after- 

 wards spread over probably many other parts of the digestive canal. 



Beside this Plexus splanchnicus superior, there is sometimes a Plexus 

 splanchnicus inferior — formed by other roots which pass off inferiorly 

 from the brain ; part of these form under the oesophagus a Ganglion pha- 

 ryngeum inferius, while others, passing backwards, constitute Nervi pha- 

 ryfigei and cesophagei}^'^^ 



The Amphinomae have on each side of the abdomen a very remarkable 

 ganglionic chain. Their ganglia intercommunicate, not only by longitudinal, 

 but also by transverse anastomoses, with the central mass of the nervous 

 system. Among these last, those which are given off from the anterior 

 lateral ganglia, join the connecting filaments of the oesophageal ring ; while 

 the others, arising from the posterior lateral ganglia, go to the various 

 ganglionic enlargements of the ventral cord.'^*^^ 



It has not yet been possible to ascertain the signification of these lateral 

 ganglionic chains. 



CHAPTER IV. 



ORGANS OF SENSE. 



I. Organs of Touch. 



With the Annelides, the sense of touch is particularly developed at the- 

 cephalic extremity. ^^> With some Lumbricini, this extremity is prolonged 

 into a kind of tentacular proboscis. ^-^ The Branchiati have special and 



15 Cuvier (Lee. d'Anat. Comp. H. 337) has no- 17 These two ganglionic chains were first de- 



ticed with Aphrodite two nerves passing Ijack- scribed by Stannius with Amphmome rostrata 



wards wliich ought to be regarded as of a splanch- (Isis, 1831, p. 986, Taf. VI. fig. 4). He saw three 



Die nature ; but Gnibe (Zur. Anat. d. Kiemen- ganglia connect with the oesophageal rnig on eacl» 



Würmer, p. 58) lias been unable to find them even side. But Grube (De Pleione carunculata, p. 10, 



in the same species. ^'i- 5) has seen six on each side with Amphinome 



IG s/anHiHS (Isis, 1831, p. 986, Taf. VI. fig. 8, r. carunculata. These lateral ganglia, moreover, 

 r.),and Grube (l)e Pleione carunculata, 1837, p 9. n-mind one of those described by fVapier, a,' al- 

 fig 5 r ) have seen with certain speefes n{ Jmphi- ready noticed with Pontnhdella muricnta. 

 name the two rfX)t8 of the Piexu.i splanchnicus 1 Acordingto Rn/h/.-^ (Danzl-. Schrift, loc. cit. 

 superior, but were unable to trace them further, p. 94, 100), the two cephalic and respu-atory fossae 

 However, with Eunice Harassii, Grube (Zur. with the Nemertini, are the seat of a most deUcate 

 Anat. d. Kiemenwiirmer, p. 43, Taf. II. fig. 9, i.) has s.M.se of touch ; and their white, long and protrac- 

 found beside tliese two roots, the Ganfi-/)on;'Aar(/n- tile proboscis is also a tactde organ. But other 

 geum superius which they form, and the nervous naturalists attribute wholly different functions to 

 filanientswhich pass off from tills last. Quite lately, tlii;se organs. 



Qnatrefases has given very exact and detailed -' The proboscis is non-articulated with Nats pro- 



descriptions and figures of the expansions of the hnscidea, a.nd Euaxes Jiliformix (Grube, f*^ieg- 



Plexus sptanchriicus superior and inferior, with 7nann\i Arch. 1844, I. p. 204, Taf. VII. nK- 1)- 



Evnice Nereis, Olycera,Phyllodoce,:ma Arid- But it is articulated with Rhynchelmis {HoJJ- 



nellaj see Ann. d. Sc. Nat. 1844, II. p. 81, I'l. 1. II. mcistcr. Ibid. 1843, 1, p. 192, Taf. IX. fig. 8). 



