NOTES ET REVUE xxix 



Villefranche, occur in tlie larva of Ph. elongatum at RoscolV, ami no 

 bristles are found in e'ilher Pli. oulgare or Ph. Gouldii. 



I hâve discovered at Woods Ilole, Mass., in living spécimens of 

 Ph. Gouldii which weie froni tliree to six cenlimeters long when 

 fully expanded, a band of six or eight irregidar rows of niiniile 

 hooks, separated from the tentacles by a narrow interval. Sliglitly 

 older spécimens (6.7 cm. and 8. cm. long) apparently do not 

 possess them, and I hâve found none in the achdl. 



Thèse studies on Phascolosoma hâve tiirown liglit on llie 

 hitherto apparently anomalous development of Sipuncnhis. Tliey 

 hâve shown that Phascolosoma is in most respects less highly 

 motlified than Sipunculus. The former is more like the Annclids 

 than the latter. 



The transitory metamerism of the mesoblastic bands and of llie 

 nerve cord, which I hâve found in Ihe trochophore of Phascolo- 

 soma, as well as many other features in the development indicale 

 the close relationship between the Sipunculids and the Annelids. 



Sipunculids are to be regarded as forms that hâve recently 

 sprungfrom the ancestralTrochozoim. The adult sipunculid rctains 

 the retractor muscles and nephridia of the trochophore. Indccd the 

 loss of the prototroch, the development of the cœlom and the enor- 

 mous elongation of the trunk are the only fundamental ciianges 

 which the trochophore andergoes in passing into the adidl 

 condition. 



COMPARAISON ENTRE SCOPELODROMUS ISEMEIUM^S 

 CHEVREL ET THALASSOMYIA FRAUENFELDI SŒl^m 



par René Giievkel 



ScfliNER a décrit, en 1856, dans Verh. d. Zool. Bot'. Vereins m 

 Wien, vol. vi, 1856, p. 215 et suivantes, un Chironomidé marm, 

 trouvé à Trieste, par Frauenfeld, sur la partie des rochers qu ar- 

 rose la pluie écumeuse des vagues, c'est-à-dire par con.séquenl 

 dans une station ayant quelque analogie avec celle où vit Scopelo- 

 dromus. Il n-eut, en sa possession, que quatre exemplaires, tous 



