198 THE GENERA OF NEMERTEANS. 



further on. So we are amply justified in proposing the 

 suppression of this name. 



Lobilabrum de Blainville must be cancelled too. Here 

 however we must motive our judgment more circumstan- 

 tially, as this genus, which was established by Blainville 

 on one specimen of a species {Lohilabrum ostrearum) never 

 since met with by any other naturalist , is remarkable 

 for the very striking characters by which it can immedia- 

 tely be distinguished from other genera. These characters 

 are: a blunt snout with two horizontal lips at the extre- 

 mity, both of them bilobed and apparently tentaculated. 

 The slit between the lips is at the same time a continua- 

 tion of the lateral fissures on both sides of the head. In 

 all other respects there is a very strong resemblance to 

 species of Linens or Cerehratulus living in the same localities. 

 One day -in Naples I was fortunate enough to get a second 

 specimen of this rare genus which, like Blainville's speci- 

 men , was collected from a bottom covered with bivalve 

 shells. It was duly figured and preserved and longitudinal 

 sections were made of the curious snout. Soon after I 

 was struck by the extraordinary resemblance in habitat 

 which existed between another Nemertean fwhose anterior 

 extremity exactly answered to that of a Lineus or a Cere- 

 hratulus and carried two well pronounced lateral fissures) 

 and this single specimen of Lobilabrmn. Once my doubts 

 raised I pursued the investigation by purposely cutting off 

 the tip of the snout in one of the last mentioned specimens 

 in a direction vertical to the body axis. Immediately the 

 curious arrangement of the lobed and tentaculated lips 

 which had hitherto been limited to the genus Lobilabrum 

 appeared, the animal lived comfortably for several weeks 

 and afterwards longitudinal sections showed that an epi- 

 dermoidal covering had made its appearance identical with 

 what had been found in the Lobilabrum specimen. Con- 

 necting these results with the fact of their living amongst 

 bivalve shells I concluded that the genus Lobilabrum was 

 established on a specimen the tip of whose snout had been 



Notes from the Leyden. ]VIuseuTn. 



