THE GENERA OF NEMERTEANS. 213 



12. Cerehratulus bilineatus Renier. 

 Synon. Lineus bilineatus Mac Intosli. 



(nee Polia bilineata delle Chiaje!) 

 Cerebraiula oerstedii van Beneden. 

 Cerebratulus taenia Mac Intosh. 

 » bivittatus Ulianin. 



Renier has given a very fair description of this species 

 which , as mentioned above , was confused with another 

 species by Blainville and delle Chiaje. This has again 

 induced Mac Intosh into error, who was the first to find 

 this species on the British coast and who felt justified in 

 identifying it with another of delle Chiaje's species which 

 (curiously enough) bears the same specific name of Polia 

 hilmeata. Delle Chiaje's last named species is however 

 quite different from the true C. bilineatus as described by 

 Renier and figured by Mac Intosh (Plate YI, fig. 1) and 

 will be noticed in its turn. We may remark that delle 

 Chiaje himself never identified his species with the one 

 described by Renier. 



I have little to add to Mac Intosh's description ; at Na- 

 ples the specimens were generally pinkish. In examining 

 very small specimens with the microscope the two dorsal 

 white lines, being less transparent, appear darker than 

 the ground-colour. 



13. Cerebratulus dellechiajei Hubr. 

 Synon. Polia bilineata delle Chiaje. 



(nee Lineus bilineatus Mac Int. !) 



This species is quite different from the foregoing and 

 seems not to be rare in the neighbourhood of Capri. Delle 

 Chiaje's figure (PI. 103) gives a very fair representation of it, the 

 dark greenish or purplish ground-colour being intersected 

 by one very thin white line in the median line of the 

 dorsum and two broad ones to the right and left of it. 

 These are continued on the head ; the belly is of a uniform 



JVotes f'roirx the Leyden Miiiseum. 



