194 FLORENCE BTTCHANAN. 



the tentacles remain attached, it is very difficult to make out 

 their point of attachment, though sections of well-preserved 

 specimens would also be of value. Meyer appears to think 

 that there is sufficient evidence of their prostomial nature, and 

 he goes on to show that both they and the branchiae of Serpulids 

 probably represent the palps, not the so-called " prostomial 

 tentacles" of the Errantia (e.g. Nereis and Polynoe).^ He 

 considers (pp. 614, 615) that there is a good deal of evidence 

 that the tentacles of Spionids originate ventrally on either 

 side of and slightly in front of the mouth, and only later move 

 upwards more on to the dorsal surface. He regards the small 

 quite anterior tentacles of Polydora antennata and others as 

 representing the *' prostomial tentacles " proper of the Errantia. 

 He also quotes in support of his view Pruvot's observations 

 on the nervous system of annelids, which led that observer to 

 conclude that the branchiae of Serpulids probably represent 

 the palps of the Errantia.- Again, he shows that in the adults 

 of some of the Spionidse (e.g. Polydora antennata), 

 Chsetopteridse (e.g. Telepsarus costarum and Phyllochae- 

 topserus), and Cirratulidse (e. g. Heterocirrus frontifilis) 

 the tentacles are much more ventrally placed than in others; and 

 in some cases, as in Heterocirrus, they are situated quite ventrally 

 in front of the mouth. In this view, if the prostomial nature of the 

 tentacles may be granted, I entirely agree with him. He might 

 also have given instances amongst the Errantia in which the palps 

 are much higher up on the lateral surface than usual, e. g. Stau- 

 rocephalus.^ It may also be of some significance, though perhaps 



of the report have taken care to figure most of the forms without their charac- 

 teristic tentacles, or else to figure the tentacles with some very limited 

 portion of the head only. 



1 For definitions of the different tentacles on the head of polycha^t worms 

 see Bourne's paper on " Haplobranchus " above referred to, footnote to p. 169. 



- 'Arch, de Zool. Experimentale,' 2ud series, vol. iii, 1SS5, pp. 314, 322. 



^ Claparede, 'Ann. Chaet. du G. dc Naples,' part i, pi. vii, fig. 2a. Cora- 

 pare also Bourne's description of the palps in the Polynoina (' Trans. Linna^an 

 Soc.,' 1883, 2nd series, " Zoology," vol. ii, part vii, p. 351). He says, " The 

 palps dill'er from all other tentacular structures in being muscular along their 

 whole length. They are capable of great elongation and contraction 



